Plus One

Reviewing Kerala Syllabus Plus One Computer Science Previous Year Question Papers and Answers Pdf Board Model Paper 2022 helps in understanding answer patterns.

Kerala Plus One Computer Science Board Model Paper 2022 with Answers

Time: 2 Hours
Total Score: 60 Marks

Answer any five questions from 1 to 7. Each carries 1 score. (5 × 1 = 5)

Question 1.
What is the major technological advancement in the fourth generation computers?
a) Transistor
b) Integrated circuit
c) Microprocessor
d) Vacuum Tube
Answer:
Micro processor

Question 2.
___________ memory is small and fast memory between the processor and RAM.
Answer:
Cache memory

Question 3.
Choose the correct exit controlled loop from the following looping statements written below:
a) while
b) for
c) do…while
d) None of the above
Answer:
do – while

Question 4.
____________ character is used as a string terminator and added at the end of the string.
Answer:
Null character(\0)

Question 5.
____________ function is used to check whether a character is in the upper case or not.
Answer:
isupper()

Question 6.
The ability of a function to call itself is known as _____________
Answer:
Recursive function

Question 7.
A ___________ is a device that can interconnect differnt networks having different protocols.
a) Router
b) Bridge
c) Switch
d) Gateway
Answer:
Gateway

Answer any 9 questions from 8 to 19. Each carries 2 scores. (9 × 2 = 18)

Question 8.
Do the following number conversions
a) (31 )₁₀ to binary. (1)
b) (10001 )₂ to decimal. (1)
Answer:
a) (31 )₁₀ = (11111)₂
b) (10001 )₂ = (17)₁₀

Question 9.
Define Data processing
Answer:
Data processing is the set of operations performed on data to produce meaningful information

Question 10.
Compare RAM and ROM
Answer:

RAM	ROM
Read and write memory (Just like our note book)	Read only memory (Just like our text book)
Faster	Slower
Volatile	Non volatile
Stores programs and data	Stores BOOT programs

Question 11.
What is an Operating System?
Answer:
It is a collection of programs that act as an interface between user and computer, without OS computer is a bare machine. Eg. MS DOS, Windows, Linux, Ubuntu,…

Question 12.
What are the two types of Documentation?
Answer:
Documentation is the last phase in programming. A computerized system must be documented properly and it is an ongoing process. It is helpful for the modification of the program later. Two types of documentations are internal and external.

Question 13.
How are non-graphic characters represented in C++? Give an example.
Answer:
It can be represented by using escape sequences, which consists of back slash(\) followed by character. Eg. \0,\n,etc

Question 14.
Write the purpose of default statement in switch statement.
Answer:
When no match is found then default statement will be executed.

Question 15.
Compare ‘break’ and ‘continue’ statements in C++.
Answer:

break	continue
Used with switch and loops	Used only with loops
It is used to quit the loop or switch	It is used to bye pass one iteration and continue the loop with next value

Question 16.
Define an array.
Answer:
An array is a collection of elements with same data type. Syntax Data_type Array_name[size];
Eg. int n[10]; It is an array of 10 integers.

Question 17.
Compare Linear search and Binary search.
Answer:

Linear Search	Binary Search
The elements need not be in an order	The elements must be in a sorted order
It may be visit all the elements	Never visit all the elements
Suitable for small sized array	Suitable for large sized array
Slower – Takes more time	Faster- Takes less time

Question 18.
Explain the merits of modular programming.
Answer:
It reduces the size of the program as well as the complexities. Hence chance of error occurrences, is less. Improves the code reusability.

Question 19.
Pick the odd one out and give reason:
a) strlen()
b) itoa()
c) strcyp()
d) strcat()
Answer:
b) itoa, it is a conversion function all others are string functions.

Answer any 9 questions from 20 to 32. Each carries 3 scores. (9 × 3 = 27)

Question 20.
Explain Von Neumann architecture of a computer with proper diagram.
Answer:

Functional units of computer
A computer is not a single unit but it consists of many functional units(intended to perform jobs) such as Input unit,Central Processing Unit(ALU and Control Unit), Storage (Memory) Unit and Output Unit.
1) Input Unit: Its aim is to supply data (Alpha-numeric, image , audio, video, etc.) to the computer for processing. The Input devices are keyboard, mouse, scanner, mic, camera, etc

2) Central Processing Unit (CPU): It is the brain of the computer and consists of three components

• Arithmetic Logic Unit(ALU) – As the name implies it performs all calculations and comparison operations.
• Control Unit(CU) – It controls over all functions of a computer
• Registers – It stores the intermediate results temporarily.

3. Storage Unit(Memory Unit): A computer has huge storage capacity. It is used to store data and instructions before starts the processing. Secondly it stores the intermediate results and thirdly it stores inf<jrmation(processed data), that is the final results before send to the output unit (Visual Display Unit, Printer, etc)

Two Types of storage unit
i. Primary Storage alias Main Memory: It is further be classified into Two- Random Access Memory (RAM) and Read Only Memory(ROM). The one and only memory that the CPU can directly access is the main memory at a very high speed. It is expensive hence storage capacity is less.

RAM is volatile (when the power is switched off the content will be erased) in nature but ROM is non volatile(lt is permanent)

ii. Secondary Storage alias Auxiliary Memory: Because of limited storage capacity of primary memory its need arises. When a user saves a file, it will be stored in this memory hence it is permanent in nature and its capacity is huge.Eg: Hard Disc Drive(HDD), Compact Disc(CD), DVD, Pen Drive, Blu Ray Disc etc.

4. Output Unit: After processing the data we will get information as result, that will be given to the end user through the output unit in a human readable form. Normally monitor and printer are used.

Question 21.
Represent-60 in 1’s complement form.
Answer:
Step 1 : Find the binary equivalent of + 60 + 60 in binary (in 8 bits) is (00111100)₂
Step 2 : To take 1 ’s complement, change all ones to zeroes and all zeroes to ones.
So -60 in 1’s complement is (11000011 )₂
Step 3 : To take 2’s complement add 1 to 1’s complement.
So -60 in 2’s complement is (11000011 )₂ + 1 = (11000100)₂

Question 22.
What is e-waste? Explain different e-waste disposal methods.
Answer:
e-Waste(electronic waste): It refers to the mal functioning electronic products such as faulty computers, mobile phones, tv sets, toys, CFL etc.

e-Waste disposal methods
a) Reuse: Reusability has an important role of e-Waste management and can reduce the volume of e-Waste
b) Incineration: It is the process of burning e-Waste at high temperature in a chimney
c) Recycling of e-Waste: It is the process of making new products from this e-Waste.
d) Land filling: It is used to level pits and cover by thick layer of soil.

Question 23.
What is mean by debugging? What are different types of errors in computer programs?
Answer:
The process of correcting errors(bugs) is called debugging. There are three types of errors Syntax error and logical error and run time error. When the programmer violates the syntactical rules then syntax error occurs and it is displayed after compilation. Eg. not using comma for multiple variable declaration, int x y z instead of int x, y, z; If the programmer makes a logical mistake then logical error occurs but it is not displayed at the time of compilation and may not get the correct answer. To find the product (*) of x and y, using + instead of *. Run time occurs during program execution

Question 24.
What are the rules for naming identifiers in C++?
Answer:
Rules for naming variables
a) A variable name must be starts with alphabets to z or A to Z) or Under score(_)
b) Digits can be used followed by an alphabet.
c) Keywords cannot be used.
d) While spaces and special characters are cannot be used.

Question 25.
Define data types in C++? List fundamental data types in C++.
Answer:

Question 26.
Rewrite the following statement using if…else statement.
result =mark>30? ‘p’: ‘f’:
Answer:
if(mark>30)
result=’p’;
else
result=’f’;

Question 27.
Write an algorithm for bubble sort.
Answer:
Following are the steps involved in bubble sort(for sorting a given array in ascending order):

1. Starting with the first element(index = 0), compare the current element with the next element of the array.
2. If the current element is greater than the next element of the array, swap them.
3. If the current element is less than the next element, move to the next element. Repeat Step 1.

Question 28.
Differentiate between ‘get()’ and ‘getline()’ functions in C++.
Answer:
get() – To read a character or characters from the keyboard. Eg.cin.get(ch); orcin.get(str,10);
getline() – To read a string with specified length from the keyboard. Eg. cin.getline(str.len);

Question 29.
Write down the differences between call by value and call by reference function calling techniques in C++.
Answer:

Call by Value Method	Call by Reference Method
Ordinary variables are used as formal parameters.	Reference variables are used as formal parameters.
Actual parameters may be constants, variables or expressions.	Actual parameters will be variables only.
The changes made in the formal arguments do not reflect in actual arguments	The changes made in the formal arguments do reflect in actual arguments.
Exclusive memory allocation is required for the formal arguments.	Memory of actual arguments is shared by formal arguments.

Question 30.
What is a computer network? What are the major advantages of a computer network?
Answer:
Computer network: Two or more computers connected through a communication media that allows exchange of information between computers is called a Computer Network. Eg: Internet

Need for network
The advantages of Networks are given below.

1. Resource sharing: All the computers in a network can share software (programs, data) and hardware (printer, scanner, CD drive etc.).
2. Reliability: If one computer fails, the other computer can perform the work without any delay. This is very important for banking, air traffic control and other application.
3. Price Vs Performance: A main frame computer can be 10 times faster than a PC but it costs thousand times a PC. Therefore instead of a main frame 10 personal computers are used with less cost and same performance.
4. Communication Medium: It is a powerful corfimunication medium. We can exchange information between computers in a network.
5. Scalable: This Means, System performance can be increased by adding computers to a network.

Question 31.
Explain the main sections of e-mail with an example.
Answer:
E mail(Electronic mail): It is used to send text, multi media messages between computers over internet. An example of an email id is jobi_cg@rediffmail.com.

The email message contains the following fields.

1. To: Recipient’s address will be enter here. Multiple recipients are also allowed by using coma.
2. CC: Enter the address of other recipients to get a carbon copy of the message.
3. bcc: The address to whom blind carbon copies are to be sent. This feature allows people to send copies to third recipient without the knowledge of primary and secondary recipients.
4. From: Address of the sender
5. Reply to: The email address to which replies are to be sent.
6. Subject: Short summary of the message.
7. Body: Here the actual message is to be typed.

Question 32.
Write the disadvantages of social media. What are the different ways to avoid the disadvantages of social media?
Answer:
Disadvantages of social media

• Intrusion to privacy: Some people may misuse the personal information.
• Addiction: sometimes it may waste time and money.
• Spread rumours: The news will spread very quickly and negatively.

The following measures can be taken to avoid disadvantages of socila media

• Avoid unnecessary uploading of personal data like e-mail address, phone number, address, pictures etc.
• Set time schedule for using different websites.
• Avoid posting wrong or misleading content on websites.
• Set privacy levels (private, friends, public) such that you know exactly who can see your posts.

Answer any 2 questions from 33 to 36. Each carries 5 scores. (2 × 5 = 10)

Question 33.
a) State De Morgan’s theorems. (2)
b) Draw logic circuit for the Boolean expression X + \(\bar{Y}\). (2)
c) Draw the logical symbol of universal gates (2)
Answer:
a) De Morgan’s theorem
Demoraan’s first theorem states that
\(\overline{X . Y}\) = \(\bar{X} . \bar{Y}\)
ie. the compliment of sum of two variables equals product of their compliments.
The second theorem states that
\(\overline{X . Y}\) = \(\bar{X} + \bar{Y}\)
ie. The compliment of the product of two variables equals the sum of the compliment of that variables

Question 34.
a) What is flowchart? List any three advantages of flowcharts. (21/2)
b) Convert the following algorithm to corresponding flowchart. (21/2)
Step 1 : START
Step 2 : Input A, B, C
Step 3 : S = A+B+C
Step 4 : Avg = S/3
Step 5 : Print S, Avg
Step 6 : STOP
Answer:
a) The diagrammatic(pictorial) representation of algorithm is called flow chart.
Advantages are

• Better communication
• Effective analysis
• Effective synthesis
• Efficient coding

b)

Question 35.
a) Write the basic structure of a C++program. (21/2)
b) Explain any one method of type conversion in C++. (21/2)
Answer:
a)

#include <iostream>
using namespace std;
int main()
{
Body of the program
return 0;
}

b) Statements: Statements are smallest executable unit of a programming language. Each and every statement must be end with semicolon(;).

Question 36.
What is Topology? Compare different LAN topologies
Answer:
Network topologies: Physical or logical arrangement of computers on a network is called structure or topology. It is the geometrical arrangement of computers in a network. The major topologies developed are star, bus, ring, tree and mesh.

1) Star Topology: A star topology has a server all ’ other computers are connected to it. If computer A wants to transmit a message to computer B. Then computer A first transmit the message to the server then the server retransmits the message to the computer B. That means all the messages are transmitted through the server. Advantages are add or remove workstations to a star network is easy and the failure of a workstation will not effect the other. The disadvantage is that if the server fails the entire network will fail.

2) Bus Topology: Here all the computers are attached to a single cable called bus. Here one computer transmits all other computers listen. Therefore it is called broadcast bus. The transmission from any station will travel in both the direction. The connected computers can hear the message and check whether it is for them or not.

Advantages are add or remove computer is very easy. It requires less cable length and the installation cost is less. Disadvantage is fault detection is very difficult because of no central computer.

3) Ring Topology: Here all the computers are connected in the shape of a ring and it is a closed loop. Here also there is no central computer. Here a computer transmits a message, which is tagged along with its destination computer’s address. The message travels in one direction and each node check whether the message is for them. If not, it passes to the next node.

It requires only short cable length. If a single node fails, at least a portion of the network will fail. To add a node is very difficult.

4) Hybrid Topology: It is a combination of any two or more network topologies. Tree topology ahd mesh topology can be considered as hybrid topology.

a) Tree Topology: The structure of a tree topology is the shape of an inverted tree with a central node and branches as nodes. It is a variation of bus topology. The data transmission takes place in the way as in bus topology. The disadvantage is that if one node fails, the entire portion will fail.

b) Mesh Topology: In this topology each node is connected to more than one node. It is just like a mesh (net). There are multiple paths between computers. If one path fails, we can transmit data through another path.

Reviewing Kerala Syllabus Plus One Computer Science Previous Year Question Papers and Answers Pdf Board Model Paper 2023 helps in understanding answer patterns.

Kerala Plus One Computer Science Board Model Paper 2023 with Answers

Time: 2 Hours
Total Score: 60 Marks

Answer any 5 questions from 1 to 6. Each carries 1 score. (5 × 1 = 5)

Question 1.
Which is the MSB representation of – 90 in the sign magnitude representation method?
Answer:
1

Question 2.
Which flowchart symbol is always used in Pair?
Answer:
Connector symbol

Question 3.
Name a ternary operator in C++.
Answer:
conditional operator

Question 4.
________ is the built in function used to terminate the program.
Answer:
exit()

Question 5.
Expand the term Wi-MAX.
Answer:
Worldwide Interoperability for microwave access

Question 6.
Acquiring information such as username, password, credit card detrails etc. using misleading websites is known as ……………………
Answer:
Phishing

Part – II

Answer any 9 questions from 7 to 18. Each carries 2 scores. (9 × 2 = 18)

Question 7.
One of the following number is invalid, find it and state the reason for invalidity.
Answer:
(a) (101001)₈
(b) (111)₂
(c) (768)₈
(d) (ABC)₁₆
Answer:
(c) (768)₈
(768)₈ is invalid because the number 8 will not be used in Octal number system.

Question 8.
Write any 2 differences between RAM and ROM.
Answer:

RAM	ROM
• It allows reading and writing.	• Allows reading only.
• It is volatile.	• Non-volatile.

Question 9.
Draw a flowchart to find the biggest of two numbers.
Answer:

Question 10.
Find the invalid identifier names from the following and give the reason for invalidity.
-8AC Z$ B7 for INT
Answer:
Z$ – $ Symbol is not allowed
for – Keyword is not allowed

Question 11.
What is L-value and R-value of a variable?
Answer:
L – value is the address and
R – value is the content of the variable

Question 12.
Compare entry controlled loop with exit controlled loop.
Answer:

Entry controlled loop	Exit controlled loop
• No guarantee to execute at least once. E.g. for, while	• Execute at least once. E.g. do while

Question 13.
List the name of any 4 operations that can be performed on an array.
Answer:
Traversing, Searching, Insertion, Deletion.

Question 14.
Write an algorithm for linear search.
Answer:
Step 1 : Start
Step 2 : Read the search element, say x
Step 3 : Compare the x with the first element.
Step 4 : if not matched, complare with the next element
Step 5 : if matched, display “element found” and go to last step
Step 6 : Repeat step 3 and 4 until the last element
Step 7 : if no match, print “Element is not found”
Step 8 : Stop

Question 15.
Distinguish between call by value and call by reference method.
Answer:

Call by value method	Call by reference method
Ordinary variables are used as formal parameters.	Reference variables are used as formal parameters.
The changes made in the formal arguments do not reflect in actual arguments.	The changes made in the formal arguments to reflect inactual arguments.

Question 16.
List the name of any 4 character functions in C++.
Answer:
isupper(), islower(), isalpha(), isdigit()

Question 17.
List and explain any 2 advantages of computer networks.
Answer:
Need for network
The advantages of Networks are given below.

1. Resource sharing: All the computers in a network can share software (programs, data …………) and hardware (printer, scanner, CD drive etc.).
2. Reliability : If one computer fails, the other computer can perform the work without any delay. This is very important for banking, air traffic control and other application.
3. Price Vs Performance: A main frame computer can be 10 times faster than a PC but it costs thousand times a PC. Therefore instead of a main frame 10 personal computers are used with less cost and same performance.
4. Communication Medium : It is a powerful communication medium. We can exchange information between computers in a network.
5. Scalable: This means, System performance can be increased by adding computers to a network.

Question 18.
Write any 4 advantages of social media.
Answer:
Social Media helps to :

1. Bring people together
2. Plan and organize events
3. Business promotion
4. Social Skills

Part – III

Answer any 9 questions from 19 to 29. Each carries 3 scores. (9 × 2 = 18)

Question 19.
Match the following:

a. ABACUS	1. Charles Babbage
b. Napier’s Bones	2. Wheels and Gears
c. Pascaline	3. Counting Frame
d. Leibnitz’s Calculator	4. Punched Card
e. Jacquard’s Loom	5. Numbering Rods
f. Analytical Engine	6. Step Reckoner

Answer:

a. ABACUS	5. Numbering Rods
b. Napier’s Bones	2. Wheels and Gears
c. Pascaline	4. Punched Card
d. Leibnitz’s Calculator	6. Step Reckoner
e. Jacquard’s Loom	1. Chrles Babbage
f. Analytical Engine	3. Counting Frame

Question 20.
Construct a logical circuit for the expression
f (a, b) = (a + b) . (\(\overline{\mathrm{a}}\) + \(\overline{\mathrm{b}}\))
Answer:

Question 21.
Categorize the software given below into operating system, application software and utility program.
Answer:
Ubuntu, Open Office Calc, Windows, WinZip, GIMP, Kaspersky
Answer:

OS	Application software	Utility program
Ubuntu, Windows	Open Office Calc, GIMP	WinZip, Kaspersky

Question 22.
Explain the different types of errors that are occurred during the compilation and running of a program.
Answer:
There are two types of errors in a program before execution and testing phase.They are syntax error and logical error. When the programmer violates the rules or syntax of the programming language then the syntax error occurred. Eg: It involves incorrect punctuation. Key words are used for other purposes, violates the structure etc,… It detects the compiler and displays an error message that include the line number and give a clue of the nature of the error. When the programmer makes any mistakes in the logic, that types of errors are called logical error. It does not detect by the compiler but we will get a wrong output. The program must be tested to check whether it is error free or not. The program must be tested by giving input test data and check whether it is right or wring with the known results. The third type of errors are Runtime errors. This may be due to the in appropriate data while execution. For example consider B/C. If the end user gives a value zero for c, the execution will be interrupted because division by zero is not possible. These situation must be anticipated and must be handled.

Question 23.
Explain any 3 Tokens available in C++.
Answer:
Token: It is the smallest individual units similar to a word in English or Malayalam language. C++ has 5 tokens
1) Keywords: These are reserved words for the compiler. We can’t use for any other purposes Eg: float is used to declare variable to store numbers with decimal point. We can’t use this for any other purpose

2) Identifier: These are user defined VvdtdS. Eg: variable name, function name, class narrle; Pbject name etc…

3) Literals (Constants): Its value does not change during execution
1) Integer literals -: Whole numbers without fractional parts are known as integer literals, its value does not change during execution. There are 3 types decimal, octal and hexadecimal.
Eg. For decimal 100, 150, etc
For octal 0100, 0240, etc
For hexadecimal 0 × 100,0 × 1 A,etc

2) Float literals -: A number with fractional parts and its value does not change during execution is called floating point literals.
Eg. 3.14157, 79.78, etc

3) Character literal-: A valid C++ character enclosed in single quotes, its value does not change during execution.
Eg. ‘m’, ‘f ’ etc

4) String literal -: One or more characters enclosed in double quotes is called string constant. A string is automatically appended by a null character(‘\0’)
Eg. “Mary’s”,’’India”,etc

Question 24.
Write another 3 forms of the C++ statement a = a +1;
Answer:
a++; ++a; a+=1;

Question 25.
What is the role of relational operators in C++? Distinguish between == and =
Answer:
== is an relational operator. It is used for comparing two expressions in C++. -’ is an assignment operator
Used to assign values from RHS to LHS.

Question 26.
Distinguish between break and continue statements in C++.
Answer:

Break	Continue
Used with switch or loops	Used only with loops
Takes the control outside the Loop	Does not take control out of loop
Causes to terminate the loop	Skips one iteration of the loop

Question 27.
Differentiate between put ( ) and write ( ) with an example.
Answer:
Output function: The outputt functions like put() (to print a character on the screen) and write() (to print a line of characters on the screen) is used with cout and dot(.) operator.

Function	Example	Description	Header file
put()	cout.put(ch) cout.put(‘a’)	To print a character on the screen	iostream
write()	cout. write (str, len)	To print a string with specified length on the sreen	iostream

Question 28.
Write a short note on any 3 network topologies.
Answer:
Bus topology – In bus topology all the nodes are connected to a main cable called bus. A small device called a terminator is attached to each end of the bus.

Star topology – In star topology each node is directly connected to a hub switch.

Ring topology in ring topology all nodes are connected using a cable that shapes like a ring or circle Data travels only in one direction in a ring.

Question 29.
Explain about the following social medias.
a) Internet Forums
b) Content communities
c) Micro blogs
Answer:
a) Internet forums : It is an online discussion site where people can exchange information about various issues like social, political, educational etc. in the text form.
b) Content communities. By using these websites we can share multi media files.
Eg. www.youtube.com
c) Microblogs : It allows users to exchange short messages, multi media files etc.
Eg. www.twitter.com

Part – IV

Answer any 2 questions from 30 to 32. Each carries 5 scores. (2 × 5 = 10)

Question 30.
(a) Explain any 3 methods of representing integer numbers in computer memory? (3)
(b) Find the one’s complement of – 38 (2)
Answer:
(a) There are three ways to represent integers in computer. They are as follows:
1) Sign and Magnitude Representation (SMR)
2) 1’s Complement Representation
3) 2’s Complement Representation

1) SMR: Normally a number has two parts sign and magnitude, eg:- Consider a number +5. Here + is the sign and 5 is the magnitude. In SMR the most significant Bit (MSB) is used to represent the sign. If MSB is 0 sign is +ve and MSB is 1 sign is-ve.
eg :- If acopiputer has word size is 1 byte then

+5 is represented as

0

0

0

0

0

1

0

1

-5 is represented as

1

0

0

0

0

1

0

1

Here MSB is used for sign then the remaining 7 bits are us£d to represent magnitude. So we can represent 27 = 128 numbers. But there are negative and positive numbers. So 128 + 128 = 256 number. The numbers are 0 to +127 and 0 to -127. Here zero is repeated. So we can represent 256 – 1 = 255 numbers.

2) 1’s Complement Representation: To get the 1 ’s complement of a binary number, just replace every 0 with 1 and every 1 with 0. Negative numbers are represented using 1’s complement but +ve number has no 1 ’s complement.
eg:- To find the 1’s complement of-21
+21 = 00010101
To get the 1 ’s complement change all 0 to 1 and all 1 to 0.
-21 = 11101010
∴ 1’s complement of -21 is 11101010
Eg: Find the 1’s complement of +21
Positive numbers are represented by using SMR.
+21 = 00010101 (No need to take the 1’s complement)

3) 2’s Complement Representation : To get the 2’s complement of a binary number, just add 1 to its 1’s complement +ve number has no 2’s complement.
eg:- To find the 2’s complement of -21
+21 =00010101
First take the 1 ’s complement for this change all 1 to 0 and all 0 to 1

∴ 2’s complement of-21 is 1110 1011

(b) (38)₁₀ = (100110)₂
So +38 = 00100110
One’s complement of-38 is 11011001
Changed all ones to zero and all zeros to one.

Question 31.
(a) What do you mean by e-Waste? (1)
(b) Explain any 4 methods of disposing e-Waste? (4)
Answer:
(a) e-Waste(electronic waste): It refers to the mal functioning electronic products such as faulty computers, mobile phones, TV sets, toys, CFL etc.

(b) e-Waste disposal methods
a) Reuse: Reusability has an important role of e-Waste management and can reduce the volume of e-Waste
b) Incineration: It is the process of burning e-Waste at high temperature in a chimney
c) Recycling of e-Waste : It is the process of making new products from this e-Waste.
d) Land filling: It is used to level pits and cover by thick layer of soil.

Question 32.
(a) Name and explain the different types of loops in C++. (3)
(b) Rewrite the following program using while loop. (2)
main( )
{
int a, p -1;
for (a = 1; a<=5; a+<2)
P=P*a;
cout<<p;
}
main( )
{
int a, p – 1;
for (a = 1; a<=5; a+<2)
p=p*a;
cout<<p;
}
Answer:
1. while statement
It is an entry controlled loop. An entry controlled loop first checks the condition and execute(or enters in to) the body of loop only if it is true. The syntax is given below
Loop variable initialised
while(expression)
{
Body of the loop;
Update loop variable;
}
Here the loop variable must be initialised before the while loop. Then the expression is evaluated if it is true then only the body of the loop will be executed and the loop variable must be updated inside the body. The body of the loop will be executed until the expression becomes false.

2. for statement
The syntax of for loop is
for(initialization; checking ; update loop variable)
{
Body of loop;
}
First part, initialization is executed once, then checking is carried out if it is true the body of the for loop is executed. Then loop variable is updated and again checking is carried out this process continues until the checking becomes false. It is an entry controlled loop.

3. do – while statement : It is an exit controlled loop. Exit control loop first execute the body of the loop once even if the condition is false then check the condition.
do
{
Statements
}while(expression);
Here the body executes at least once even if the condition is false. After executing the body it checks the expression if it false it quits the body otherwise the process will be continue.

b)
main()
{.
int a=1,p=1;
while(a<=5)

Reviewing Kerala Syllabus Plus One Computer Science Previous Year Question Papers and Answers Pdf SAY 2019 helps in understanding answer patterns.

Kerala Plus One Computer Science Previous Year Question Paper SAY 2019

Time: 2 Hours
Total Score: 60 Marks

Answer all questions from 1 to 5. Each carries 1 score. (5 × 1 = 5)

Question 1
………………… was discovered by the Mesopotamians around 3000 B.C.
Answer:
Abacus

Question 2.
Each digit of a binary number is called ……………………. .
Answer:
bit

Question 3.
How many bytes are required to store the string “HELLO WORLD”?
Answer:
12 (including 1 bit for null character)

Question 4.
What do you mean by IP Address?
Answer:
An IP(lnternet Protocol) address has 4 parts numeric address separated by dots(.).

Question 5.
Name two input stream functions in C++.
Answer:
get() or gerline().

Answer any 9 questions from 6 to 16. Each carries 2 scores. (9 × 2 = 18)

Question 6.
Write short note on First Generation Computers.
Answer:
First generation computers (1940 – 1956)
Vacuum tubes were used in first generation computers. The input was based on punched cards and paper tapes and output was displayed on printouts. The Electronic Numerical Integrator and Calculator(ENIAC) belongs to first generation was the first general purpose programmable electronic computer built by J. Presper Eckert and John V. Mauchly. It was 30 – 50 feet long, weight 30 tons, 18,000 vacuum tubes, 70,000 registers, 10,000 capacitors and required 1,50,000 watts of electricity. It requires Air Conditioner. They later developed the first commercially successful computer, the Universal Automatic Computer(UNIVAC) in 1952.
Von Neumann architecture

The mathematician John Von Neumann designed a computer structure that structure is in use nowadays. Von Neumann structure consists of a central processing unit(CPU),Memory unit, Input and Output unit. The CPU consists of arithmetic logical unit(ALU) and control unit(CU). The instructions are stored in the memory and fallows the “Stored Program Concept”. Colossus is the secret code breaking computer developed by a British engineer Tommy Flowers in 1943 to decode German messages.

Question 7.
What do you mean by Programming Languages? Briefly explain.
Answer:
We know that a program is a set of instructions that tell the hardware how to perform a task. This can be written in different languages, such as C, C++, COBOL, PASCAL, JAVA, etc.

Question 8.
If (x)₈ = (101011)₂ = (y)₁₆. Find the values of x and y.
Answer:
(x)₈ = (101011 )₂ = (y)₁₆
i) To convert a binary number into octal first divide the-number into groups of 3 bits and then write down the binary equivalent. Here 101 – 5 and 011 – 3.
(101011 )₂ = (53)₈ So x = 53.

ii) To convert a binary number into hexadecimal first divide the number into groups of 4 bits starting from the right and insert 2 zeroes in the left side and then write down the binary equivalent.
(00101011)₂ =(y)₁₆
Here 0010 – 2 and 1011 – 11(lt is B). So y = 2B.

Question 9.
Write short note on character set of C++.
Answer:
Character set:- To study a language first we have to familiarize the character set. For example to study English language first we have to study the alphabets. Similarly here the character set includes letters(A to Z & a to z), digits(0 to 9), special characters(+, – , ?, *, /, ………) white spaces(non printable) etc..

Question 10.
Define the term variable. Write the correct syntax to declare a variable.
Answer:
A variable is a named storage location inside the
memory. Syntax: Data_Type Variable_name1,Variable_Name2,…;
Eg. int x, y, z;

Question 11.
Write the use and syntax of the following operators in C++:
a) Conditional operator (?:)
b) Size of operator (?:)
Answer:
a) Conditional operator It is a ternary operator hence it needs three operands. The operator is?:. Syntax: expression ? value if true: value if false. First evaluates the expression if it is true the second part will be executed otherwise the third part will be executed.
Eg. If x= 10 and y=3 then
x>y ? cout< Here the output is 10

b) sizeof(): This operator is used to find the size used by each data type.
Eg. sizeof(int) gives 2.

Question 12.
Compare for loop and do-while loop in C++.
Answer:

for loop	do while loop
Entry controlled	Exit controlled
The number of iterations known in advance then for loop is used	The number of iterations not known in advance then do while loop is used
The body will be executed only if the test expression becomes true.	But here the body executes at least once even if the condition is false.

Question 13.
Breifly explain about two types of sorting methods.
Answer:
Sorting – Arranging elements of an array in an order(ascending or descending)

• Bubble sortIt is a simple sorting method. In this sorting considering two adjascent elements if it is out of order, the elements are interchanged. After the first iteration the largest(in the case of ascending sorting) or smallest(in the case of descending sorting) will be the end of the array. This process continues.
• Selection sortIn selection sort the array is divided into two parts, the sorted part arid unsorted part. First smallest element in the unsorted part is searched and exchanged with the first element. Now there is 2 parts sorted part and unsorted part. This process continues.

Question 14.
Illustrate the concept of two dimensional arrays.
Answer:
Matrix is a concept in mathematics that can be represented by 2D array with rows and columns. A nested loop(a loop contains another loop) is used to store and access elements in an array.

Question 15.
Write short notes on:
a) Bluetooth
b) WiFi
Answer:
1. Bluetooth: This technology uses radio waves in the frequency range of 2.402 GHz to 2.480 GHz. And transmit data in short distance. Mobile phones, Laptops, tablets etc use Bluetooth technology to transmit data.

2. Wi Fi(Wireless Fidelity): It uses radio waves to transmit information across a network in a range 2.4 GHz to 5 GHz in short distance. Nowadays this technology is used to access internet in Laptops, Desktops, tablets, Mobile phones etc.

Question 16.
Describe briefly about any two advantages of Email.
Answer:
Advantages of Email are

• High speed
• It is cheap
• Can send multiple recipients
• It reduces usage of paper.
• Incoming messages can be saved locally

Answer any 9 questions from 17 to 27. Each carries 3 stores. (9 × 3 = 27)

Question 17.
Explain about any three number systems.
Answer:
Number System: It is a systematic way to represent numbers in different«ways. Each number system has its own Base, that is a number and that number of symbols or digits used.
The various number systems are given below:

Question 18.
Write notes on:
a) ASCII
b) Sign Magnitude
c) Unicode
Answer:
a) ASCII-American Standard Code for Information Interchange. It is a 7bit code introduced by US Govt, for storing alphanumeric and some special characters in computer memory.

b) Sign Magnitude- It is one method used to represent integers in computer. Normally an integer has two parts sign and magnitude. In SMR MSB(0 for positive and 1 for negative) is used to represent sign and the remaining bits are used to represent magnitude.

c) Unicode – It is an universal code. The limitations to store more characters is solved by the introduction of Unicode.

Question 19.
Define the term E-waste. Explain briefly about any two E-waste disposal methods.
Answer:
e-Waste(electronic waste): It refers to the mal functioning electronic products such as faulty computers, mobile phones, tv sets, toys, CFL etc.

e-Waste disposal methods
a) Reuse: Reusability has an important role of e-Waste management and can reduce the volume of e-Waste
b) Incineration: It is the process of burning e Waste at high temperature in a chimney
c) Recycling of e-Waste: It is the process of making new products from this e-Waste.
d) Land filling: It is used to level pits and cover by l thick layer of soil.

Question 20.
Use the proper symbols to complete the flowchart given below:

Answer:

Question 21.
Define the following terms:
a) Syntax Error
b) Algorithm
c) Debugging
Answer:
a) When the rules or syntax of the language are not followed then syntax error occurred and it is displayed after compilation.
b) The step by step procedure to solve a problem is known as algorithm.
c) The process of detecting and correcting errors is called debugging.

Question 22.
Explain about any three types of tokens used in C++.
Answer:
Token: It is the smallest individual units similar to a word in English or Malayalam language. C++ has 5 tokens
1) Keywords
These are reserved words for the compiler. We can’t use for any other purposes Eg: float is used to declare variable to store numbers with decimal point. We can’t use this for any other purpose

2) Identifier : These are user defined words. Eg: variable name, function name, class name, object name etc…

3) Literals (Constants): Its value does not change during execution
1) Integer literals -: Whole numbers without fractional parts are known as integer literals, its value does not change during execution. There are 3 types decimal, ot:tal and hexadecimal.
Eg. For decimal 100, 150, etc
For octal 0100, 0240, etc
For hexadecimal 0 × 100,0 × 1 A,etc

2) Float literals -: A number with fractional parts and its value does not change during execution is called floating point literals.
Eg. 3.14157, 79.78, etc

3) Character literal-: A valid C++ character enclosed in single quotes, its value does not change duHng execution.
Eg. ‘m’, ‘f’ etc

4) String literal -: One or more characters enclosed in double quotes is called string constant. A string is automatically appended by a null character(‘\0’)
Eg. “Mary’s”,’’India”,etc

Question 23.
Describe any three datatypes in C++.
Answer:
Fundamental data types: It is also called built in data type. They are int, char, float, double and void
i) int data type-: It is used to store whole numbers without fractional (decimal point) part. It can be either negative or positive. It consumes 4 bytes (32 bits) of memory.i.e. 2³² numbers. That is 2³¹ negative numbers and 2³¹ positive numbers (0 is considered as +ve ) So a total of 2³² numbers. We can store a number in between – 2³¹ to + 2³¹ – 1.

ii) char data type :- Any symbol from the key board, eg. ‘A’,’?’, ‘9’ It consumes one byte( 8 bits) of memory. It is internally treated as integers, i.e. 2⁸ = 256 characters. Each character is having a ASCII code, ‘a’ is having ASCII code 97 and zero is having ASCII code 48.

iii) float data type:- It is used to store real numbers i.e. the numbers with decimal point. It uses 4 bytes(32 bits) of memory. Eg. 67.89, 89.9 E-15.

Question 24.
Write the syntax and use of following functions in C++ :
a) Strcpy ()
b) pow ()
c) islower()
Answer:
a) strcpy() – It is used to copy a second string into first string.
Syntax: strcpy(string1, string2);
Eg. strcpy(str,” Covid 19”);

b) pow() – To find the power of a number.
Syntax: pow(number1, number2);
Eg. cout<<pow(5, 3); It is equivalent to 53.

c) islower() – To check whether the given character is in lower case or not. If the character is in lower case it returns a value 1 otherwise 0. Syntax: islower(‘n’); It returns 1.

Question 25.
Differentiate between call by value and call by reference methods.
Answer:
1) Call by value: In call by value method the copy of the original value is passed to the function, if the function makes any change will not affect the original value.
Example

# include <iostream.h> 
# include<conio.h>
void swap(int a, int b)
{
int temp;
temp=a;
a=b;
b=temp;
}
main()
{
clrscr();
int a,b;
cout<<“Enter values for a and b:- “; cin>>a>>b;
cout<<“The values before swap a=”<<a<<“ and
b=”<<b;
swap(a,b);
cout<<“\nThe values before swap a=”<<a<<“ and
b=”<<b;
getch();
}

2) Call by reference: In call by reference method the address of the original value is passed to the function, if the function makes any change will affect the original value.
Example

# include <iostream.h> 
# include<conio.h>
void swap(int &a, int &b)
{
int temp;
temp=a;
a=b;
b=temp;
}
main()
{
clrscr();
int a,b;
cout<<“Enter values for a and b:- “; cin>>a>>b;
cout<<“The values before swap a=”<<a<<“ and
b=”<<b;
swap(a,b);
cout<<“\nThe values before swap a=”<<a<<“ and
b=”<<b; 
getch(); 
}

Question 26.
Consider the following figure and answer the questions.
My_name

a) Write the decalration statement for the above array in C++.

b) Write the C++ statement to input the string “WEL-COME” into the array. c) Name the header file required if the elements of the array are to be printed using puts() function.
Answer:
a) char My_name[10];
b) gets(My_name) or cin>>My_name;
c) cstring

Question 27.
Compare the dial up connection and Wired boradband connection.
Answer:

Dial up Connection	Wired Broadband connection
To connect to the internet need to dial ISP	No need to dial
It is slower	It is high speed
Error rate is high	Error rate is low
It is not always on connection	It is always on connection

Answer any 2 questions from 28 to 30. Each carries 5 Scores. (2 × 5 = 10)

Question 28.
Explain the features of any five input devices of a computer.
Answer:
An input device is used to supply data to the computer. They are given below:
1) Key board : It is the most widely used device to input information,in the form of words, numbers etc.

2) Mouse : It is a pointing device, that controls the movement of the cursor, or pointer as a display screen.

3) Optical Mark Reader (OMR): This device identifies the presence or absence of a pen or pencil mark. It is used to evaluate objective type exams. In this method special preprinted forms are designed with circles can be marked with dark pencil or ink. A high intensity beam in the OMR converts this into computer usable form and de-tects the number and location of the pencil marks. By using this we can evaluate easily and reduce the errors.

4) Bar code / Quick Response (QR) code reader: Light and dark bars are used to record item name, code and price is called Bar Code. This information can be read and input into a computer quickly without errors using Bar Code Readers. It consists of a photo electric scanner and it is used in super market, jewellery, textiles etc.
QR codes are similar to barcodes but it uses two dimensional instead of single dimensional used in Barcode.

5) Joy Stick: It is a device that lets the user move an object quickly on the screen. It has a liver that moves in’all directions and controls the pointer or object. It is used for computer games and CAD / CAM systems.

Question 29.
Explain about the five jump statements in C++.
Answer:
The execution of a program is sequential but we can change this sequential manner by using jump statements. The jump statements are
1. goto statement:- By using goto we can transfer the control anywhere in the program without any condition. The syntax is goto label;

Eg. 
# include <iostream> 
using namespace std; 
int main() 
{ float a,b; 
cout<<"Enter 2 numbers"; cin>>a>>b; 
if(b==0) 
goto end; 
cout<<"The quotient is "<<a/b; 
return 0; 
end:cout<<"Division by zero error"; 
}

2. break statement:- It is used to skip over a part of the code i.e. we can premature exit from a loop such as while, do-while, for or switch.

Syntax:
while (expression)
{
if (condition)
break;
}
Eg.
#include
using namespace std;
main()
{
int i=1;
while(i<10)
{
cout<<i<<endI;
if(i==5)
break;
i++;
}
}
The output is
1
2
3
4
5

3. continue statement:- It bypasses one iteration of the loop.

Syntax:
while (expression)
{
if (condition) 
break;
}
Eg.
#include<iostream> 
using namespace std; 
main()
{
int i=0;
while(i<10) 
{ 
i++;
if(i==5) continue; 
cout<<i<<endI;
} 
}
The output is 
1 
2
3
4
6
7
3 
9
10

4. exit(0) function:- It is used to terminate the program. For this the header file cstdlib must be included.

Question 30.
Define network topology. Explain about the four major topologies.
Answer:
Topology: The way in which the nodes are physically interconnected to form a network.
• Bus topology
• Star topology
• Ring topology
• Mesh topology
Bus topology- In bus topology all the nodes are connected to a main cable called bus. A small device called a terminator is attached to each end of the bus.

Star topology- In star topology each node is directly connected to a hub switch.

Ring topology -In ring topology all nodes are connected using a cable that shapes like a ring or circle Data travels only in one direction in a ring.

Mesh topology- In mesh topology every node is connected to other nodes.’There will be more than one path between two nodes.

Reviewing Kerala Syllabus Plus One Computer Science Previous Year Question Papers and Answers Pdf March 2019 helps in understanding answer patterns.

Kerala Plus One Computer Science Previous Year Question Paper March 2019

Time: 2 Hours
Total Score: 60 Marks

Answer all questions from 1 to 5.
Each carry 1 score. (5 × 1 = 5)

Question 1.
The number of symbols used in a number system is ……………………. .
Answer:
Base or Radix

Question 2.
Small and fast memory between processor and RAM is called ……………………. .
Answer:
Cache memory

Question 3.
What is the use of Rhombus symbol in flowchart?
Answer:
Decision making or condition checking

Question 4.
To find the number of characters in a string, ……………………. function is used.
Answer:
strlen()

Question 5.
To check an alphabet is lowercase, …………………… function can be used.
Answer:
islower()

Answer any 9 questions from 6 to 16.
Each carries 2 scores. (9 × 2 = 18)

Question 6.
Expand the following:
a) ENIAC
b) VLSI
Answer:
a) Electronic Numeric Integrator and Calculator
b) Very Large Scale Integrated

Question 7.
State De’Morgan’s theorems.
Answer:
(A+B)’ = A . B’
(A.B)’ = A’ + B’

Question 8.
Name any four e-Waste disposal methods.
Answer:
e-Waste disposal methods
a) Reuse: Reusability has an important role of e – Waste management and can reduce the volume of e-Waste
b) Incineration: It is the process of burning e Waste at high temperature in a chimney
c) Recycling of e-Waste: It is the process of making new products from this e-Waste.
d) Land filling: It is used to level pits and cover by thick layer of soil.

Question 9.
Compare Entry Controlled loop with Exit Controlled loop.
Answer:
An entry controlled loop first checks the condition and execute(or enters in to) the body of loop only if it is true. But exit control loop first execute the body of the loop once even if the condition is false then check the condition. The for loop and while loop are entry controlled loops but do- while loop is an exit controlled loop.

Question 10.
Find the invalid identifier npmes from the following: A1, d-w, 999, qwA, Z$, AaA1, 8c
Answer:
Invalid identifiers
d-w(Special characters not allowed)
999(Cannot be start with a number)
z$($ not allowed)
8c(Cannot be start with a number)

Question 11.
List the datatype modifiers used in C++.
Answer:
With the help of type modifiers we can change the sign and range of data with same size. The important modifiers are signed, unsigned, long and short.

Question 12.
Write the symbols of the following C++ operators.
a) Conditional operator
b) Extraction operator
c) Increment operator
d) NOT operator
Answer:
a) ?:
b) <<
c) ++
d) !

Question 13.
Write the syntax of if ………………… else statement.
Answer:

if(Test expression)
{
statement block 1;
}
else
{
statement block 2;
}

Question 14.
Compare Linear search with Binary search.
Answer:

Linear	Binary
no need of sorted array	need of sorted array
searching is slower for larger array	It is fester
It starts checking from the first element and checks all elements.	Divide and conquer method used

Question 15.
What do you mean by argument of a function? Explain formal arguments.
Answer:
To invoke a function that requires some data for performing the task, such data is called parameter or argument.
The parameters appear in a function definition are formal arguments.

Question 16.
Write the advantages of social media.
Answer:
Advantages of social media.

• Bring people together: It allows people to maintain the friendship
• Plan and organize events: It allows users to plan and organize events.
• Business promotion: It helps the firms to promote their sales.
• Social skills: There is a key role of the formation of society.

Answer any 9 questions from 17 to 27. Each carries 3 scores. (9 × 3 = 27)

Question 17.
Explain any three generations of computers.
Answer:
There are five generations of computers from 16 th century to till date.
1) First generation computers (1940 – 1956)
Vacuum tubes were used in first generation computers. The input was based on punched cards and paper tapes and output was displayed on printouts.

2) Second generation computers (1956 – 1963)
Transistors, instead of Vacuum tubes, were used in 2nd generation computers hence size became smaller, less expensive, less electricity consumption and heat emission and more powerful and faster.

3) Third generation computers (1964 – 1971)
Integrated Circuits(IC’s) were used. IC’s or silicon chips were developed by Jack Kilby, an engineer in Texas Instruments. It reduced the size again and increased the speed and efficiency.

4) Fourth generation computers (1971 onwards)
Microprocessors are used hence computers are called microcomputers.

5) Fifth generation computers (future)
Fifth generation computers are based on Artificial Intelligence(AI). Al is the ability to act as human intelligence like speech recognition, face recognition, robotic vision and movement etc.

Question 18.
Draw the logic circuit of Boolean expression X . Y + \(\bar{Y}\)
Answer:

Question 19.
Convert(11011)₂ to Octal decimal and Hexadecimal number systems.
Answer:
a) To octal-for this divide the number into groups of 3 bits starting from the right and write down the corresponding octal equivalent
011 011 → 33
(11011)₂ = (33)₈

b) To decimal – for this multiply each digit by its corresponding weight and sum it up.
(11011)₂ = (27)₁₀

c) To Hexadecimal – for this divide the number into groups of 4 bits starting from the right and write down the corresponding hexadecimal equivalent
0001 1011 → 1 B
(11011 )₂ =(1B)₁₆

Question 20.
Name the steps involved in problem solving.
Answer:

1. Problem identification :
2. Deriving the steps to obtain the solution.
3. Coding
4. Translation
5. Debugging
6. Execution and Testing
7. Documentation

Question 21.
Write a short note on C++ character set.
Answer:
The character set of C++ is given below
a) Letters – A to Z and a to z.
b) Digits – 0 to 9
c) Special characters – +,-,*,/ etc
d) White spaces(non printable characters) and other characters

Question 22.
Describe three types of C++ expressions with an example.
Answer:
An expression is composed of operators and operands

1. Arithmetic – It consists of arithmetic operators and operands eg. a+5, b%10, etc
2. Relational – It consists of relational operators and operands eg. a>5, b==5, etc
3. Logical – It combines two or more relational expressions with logical operators. Eg. x>y && x==z

Question 23.
Write an algorithm for selection sort.
Answer:
Selection sort: In selection sort the array is divided into two parts, the sorted part and unsorted part. First smallest element in the unsorted part is searched and exchanged with the first element. Now there is 2 parts sorted part and unsorted part. This process continues.

Algorithm
Step 1. Start
Step 2. Read N(The number of elements)
Step 3. Read N elements into the Array AR
Step 4. Repeat steps.5 to 8, (N-1) times
Step 5. Assume that the first element is the smallest and set into MIN, and its position is POS
Step 6. Repeat Step 7 until the last element of the list
Step 7. Compare MIN with the remaining elements and the smaller one is stored in the MIN(Swap) and its position in POS
Step 8. Revise the list by excluding the first element in the list
Step 9. Print the Sorted Array AR
Step 10. Stop.

Question 24.
Differentiate between put ( ) and write ( ) with an example.
Answer:
put()- This is used to print a character on the screen. Eg. cout.put(“A”);
write() – This is used to print a string with specified length on the screen. Eg. cout.write(str,len);

Question 25.
Describe the merits of modular pro-gramming.
Answer:
Merits of modular programming is

1. It reduces the size of the program
2. Less chance of error
3. It reduces programming complexity
4. It improves reusability

Question 26.
Write short notes on.
a) Bluetooth
b) Wi-Fi
c) Satellite
Answer:
a) Bluetooth: This technology uses radio waves in the frequency range of 2.402 GHz to 2.480 GHz. And transmit data in short distance. Mobile ,• phones, Laptops, tablets etc use Bluetooth technology to transmit data.

b) Wi Fi(Wireless Fidelity): It uses radio waves to transmit information across a network in a range 2.4 GHz to 5 GHz in short distance. Nowadays this technology is used to access internet in Laptops, Desktops, tablets, Mobile phones etc.

c) Satellites : By using satellite we can communicate from any part of the world to any other. The ground stations are connected via the satellite. The data signals transmitted from earth to satellite (uplink) and from the satellite to the earth (downlink).

Question 27.
What is the role of Firewall and Anti-virus scanner in computer networks?
Answer:
Firewall: It is a system that controls the incoming and out going network traffic by analyzing the data and then provides security to the computer network in an organization from other network (internet).

Antivirus scanners : It is a tool used to scan computer files for viruses, worms and Trojan horses and cure the infected system. If any fault found it stops the file from running and stores the file in a special area called Quarantine(isolated area) and can be deleted later.

Answer any 2 questions from 28 to 30. Each carries 5 scores. (2 × 5 = 10)

Question 28.
a) Write any two examples of optical storage devices. (1)
b) Rearrange the following memories in descending order depending on their speed.
(Hard disk, RAM, Cache Memory, Registers) (2)
c) List four major functions of operating system. (2)
Answer:
a) CD, DVD, Blue Ray Disc
b) Registers,Cache Memory, RAM, Hard Disk
c) Process management, Memory handling, Device management and file management

Question 29.
a) Explain any three jump statements with examples. (3)
b) Read the following C++ statement and rewrite using if ……….. else.
(a>b)? cout<<a:
cout<<b; (2)
Answer:
a) 1) goto statement By using goto we can transfer the control anywhere in the program without any condition. The syntax is goto label;

Eg.
#include
using namespace std; ”
intmain()
{
float a,b;
cout<<“Enter 2 numbers”; cin>>a>>b;
if(b==0)
goto end;
cout<<“The quotient is “<<a/b;
return 0;
end:cout<<“Division by zero error”;
}

2) break statement:- It is used to skip over a part of the code i.e. we can premature exit from a loop such as while, do-while, for or switch.

Eg.
#include
using namespace std;
main()
{
int i=1;
while(i<10)
{
cout<<i<<endI;
if(i==5)
break;
i++;
}
}

3) continue statement :- It bypasses one iteration of the loop.

Eg.
#include
using namespace std;
main()
{
int i=0;
while(i<10)
{
i++;
if(i==5) continue;
cout<<i<<endI; } } b) it(a>b)
cout<<a;
else
cout<<b;

Question 30.
Explain the network topologies with diagrams.
Answer:
The major topologies developed are star, bus, ring, tree and mesh.

1) Star Topology: A star topology has a server all other computers are connected to it. If computer A wants to transmit a message to computer B. Then computer A first transmit the message to the server then the server retransmits the message to the computer B. That means all the messages are transmitted through the server. Advantages are add or remove workstations to a star network js easy and the failure of a workstation will not effect the other. The disadvantage is that if the server fails the entire network will fail.

2) Bus Topology: Here all the computers are attached to a single cable called bus. Here one computer transmits all other computers listen. Therefore it is called broadcast bus. The transmission from any station will travel in both the direction. The connected computers can hear the message and check whether it is for them or not.

Advantage are add or remove computer is very easy. It requires less cable length and the installation cost is less. Disadvantage is fault detection is very difficult because of no central computer.

3) Ring Topology: Here all the computers are connected in the shape of a ring and it is a closed loop. Here also there is no central computer. Here a computer transmits a message, which is tagged along with its destination computer’s address. The message travels in one direction and each node check whether the message is for them. If not, it passes to the next node.

It requires only short cable length. If a single node fails, at least a portion of the network will fail. To add a node is very difficult.

4) Hybrid Topology: It is a combination of any two or more network topologies. Tree topology and mesh topology can be considered as hybrid topology.

a) Tree Topology: The structure of a tree topology is the shape of an inverted tree with a central node and branches as nodes. It is a variation of bus topology. The data transmission takes place in the way as in bus topology. The disadvantage is that if one node fails, the entire portion will fail.

b) Mesh Topology: In this topology each node is connected to more than one node. It is just like a mesh (net). There are multiple paths between computers. If one path fails, we can transmit data through another path.

Reviewing Kerala Syllabus Plus One Maths Previous Year Question Papers and Answers Pdf Board Model Paper 2018 helps in understanding answer patterns.

Kerala Plus One Maths Board Model Paper 2018 with Answers

Time: 2 Hours
Total Scores: 60

Answer any six questions from 1 to 7. Each carries 3 scores.

Question 1.
Consider the Venn diagram given below:

(a) Write A’, B’, (A ∩ B)’ (2)
(b) Verify that (A ∩ B)’ = A’ ∪ B’ (1)
Answer:
(a) A’ = {5, 6, 7, 8, 9}, B = {1, 2, 7, 8, 9}
(A ∩ B)’ = {1, 2, 5, 6, 7, 8, 9}
(b) A’ ∪ B’ = {1, 2, 5, 6, 7, 8, 9}
Hence (A ∩ B)’ = A’ ∪ B’

Question 2.
For any triangle ABC, prove that \(\sin \left(\frac{B-C}{2}\right)=\frac{b-c}{a} \cos \left(\frac{A}{2}\right)\)
Answer:

Question 3.
Consider the complex number z = 3 + 4i
(a) Write the conjugate of z. (1)
(b) Verify that z\(\bar{z}\) = |z|² (2)
Answer:

Question 4.
(a) Solve the inequality -5 ≤ \(\left(\frac{5-3 x}{2}\right)\) ≤ 8 (2)
(b) Represent the solution on a number line. (1)
Answer:

Question 5.
4 cards are drawn from a well shuffled pack of 52 cards.
(a) In how many ways can this be done? (1)
(b) In how many ways can this be done if all 4 cards are of the same colour? (2)
Answer:
(a) No. of ways = ⁵²C₄
(b) No. of ways, all 4 are same colour = ²⁶C₄ + ²⁶C₄ = 2 × ²⁶C₄

Question 6.
Consider the equation of the ellipse 9x² + 4y² = 36. Find
(a) Focii (1)
(b) Eccentricity (1)
(c) Length of latus rectum (1)
Answer:

Question 7.
Evaluate \(\lim _{x \rightarrow-1} \frac{2 x+8}{x^2+x-12}\)
Answer:

Answer any eight questions 8 to 17. Each carries 4 scores each.

Question 8.
Consider A = {x : x is an integer, 0 < x ≤ 3}
(a) Write A in roster form. (1)
(b) Write the power set of A. (1)
(c) The number of proper subsets of A. (1)
(d) Write the number of possible relations from A to A. (1)
Answer:
(a) A = {1, 2, 3}
(b) P(A) = {φ, {1}, {2}, {3}, {1, 2}, {1, 3}, {2, 3}, {1, 2, 3}}
(c) Number of proper subset = 2³ – 1 = 7
(d) Number of relations = 2^3×3 = 512

Question 9.
Consider the statement P(n): \(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+\ldots \ldots .+\frac{1}{n(n+1)}=\frac{n}{n+1}\)
(a) Show that P(1) is true. (1)
(b) Prove that P(n) is true for all n ∈ N using the principle of Mathematical induction. (3)
Answer:


Hence, by using the principle of mathematical induction true for all n ∈ N.

Question 10.
Consider the complex number z = \(\frac{1+3 i}{1-2 i}\)
(a) Write z in the form a + ib. (1)
(b) Write z in polar form. (3)
Answer:

Question 11.
Solve the following inequalities graphically:
x – 2y ≤ 3; 3x + 4y ≥ 12; x ≥ 0; y ≥ 1
Answer:

Question 12.
(a) How many 3-letter words with or without meaning can be formed using 26 letters in the English alphabet, if no letter is repeated? (1)
(b) Find the number of permutations of letters of the word MATHEMATICS. (2)
(c) How many of them begin with the letter C? (1)
Answer:
(a) No. of words = ²⁶P₃ = 15600
(b) In the word MATHEMATICS, the letters M-2, A-2, T-2, H-1, E-1, I-1, C-1, S-1 are repeated.
No. of permutation = \(\frac{11!}{2!\times 2!\times 2!}\)
(c) If the words begin with C = \(\frac{10!}{2!\times 2!\times 2!}\)

Question 13.
Consider the figure given below. A(3, 0) and B (0, 2) are two points on the axes. The line is perpendicular to AB.

(a) Find the slope of OP. (1)
(b) Find the coordinate of the point P. (3)
Answer:

Question 14.
Equation of the parabola given in the figure is y² = 8x.

(a) Find the focus and length of latus rectum of the parabola. (2)
(b) The latus rectum of the parabola is a chord to the circle centered at the origin as shown in the figure. Find the equation of the circle. (2)
Answer:
(a) The equation parabola is y² = 8x
⇒ a = 2
Length of latus rectum = 4a = 4 × 2 = 8
(b) A and B are extremities of the latus rectum. Hence the coordinate of A is (a, -2a) = (2, -4) and that of B is (a, 2a) = (2, 4)
Therefore, the radius of the circle is the distance from A or B
Radius = \(\sqrt{(2-0)^2+(4-0)^2}=\sqrt{4+16}=\sqrt{20}\)
Equation of the circle is x² + y² = 20

Question 15.
Let L be the line x – 2y + 3 = 0
(a) Find the equation of the line L₁ which is parallel to L and passing through (1, -2). (2)
(b) Find the distance between L and L₁. (1)
(c) Write the equation of another line L₂ which is parallel to L, such that the distance from the origin to L and L₂ are the same. (1)
Answer:
(a) Slope of the line L is \(\frac{1}{2}\)
The slope of parallel line L₁ is \(\frac{1}{2}\)
Therefore, the equation of line L₁
y – (-2) = \(\frac{1}{2}\) (x – 1)
⇒ 2(y + 2) = x – 1
⇒ 2y + 4 = x – 1
⇒ x – 2y – 5 = 0
(b) Distance between L and L₁ = \(\left|\frac{-5-3}{\sqrt{(1)^2+(-2)^2}}\right|=\frac{8}{\sqrt{5}}\)
(c) The equation of the line L₂ will be on the other side of the origin.
So the equation of L₂ can be obtained by changing the sign of the constant term in the equation of L = x – 2y – 3 = 0

Question 16.
Consider a point A(3, 2, -1) in space
(a) Write the octant in which A belongs to (1)
(b) If B (1, 2, 3) is another point in Space, find the distance between A and B. (1)
(c) Find the coordinate of the point R which divides AB in the ratio 1 : 2 internally. (2)
Answer:
(a) 5th octant.

Question 17.
a) Write the contrapositive of the statement. (1)
p: If a triangle is equilateral, then it is isosceles.
b) Verify by method of contradiction: ‘√3 is irrational’ (3)
Answer:
(a) If a triangle is not isosceles, then it is not equilateral.
(b) Assume that √3 is rational. Then √3 can be written in the form \(\sqrt{3}=\frac{p}{q}\), where p and q are integers without common factors.
Squaring: 3 = \(\frac{p^2}{q^2}\)
⇒ 3q² = p² …….(1)
⇒ 3 divides p²
⇒ 3 divides p
Therefore, p = 3k for some integer k.
⇒ p² = 9k²
(1) ⇒ 3q² = 9k²
⇒ q² = 3k²
⇒ 3 divides q²
⇒ 3 divides q
Hence p and q have a common factor 3, which contradicts our assumption. Therefore, √3 is irrational.

Answer any 5 questions from 18 to 24. Each carries 6 scores.

Question 18.
(a) If A = {a, b} write A × A × A. (2)
(b) If R = {(x, x³) : x is a prime number less than 10}. Write R in roster form. (2)
(c) Find the domain and range of the function f(x) = 2 + \(\sqrt{x-1}\) (2)
Answer:
(a) A × A × A = {(a, a, a), (a, a, b), (a, b, a), (a, b, b), (b, a, a),(b, a, b), (b, b, a), (b, b, b)}
(b) R = {(2, 8), (3, 27), (5, 125), (7, 343)}
(c) Domain = [1, ∞)
Range = [2, ∞)

Question 19.
(a) The minute hand of a watch is 3 cm long. How far does its tip move in 40 minutes? (2)
(Use π = 3.14)
(b) Solve the trigonometric equation sin 2x – sin 4x + sin 6x = 0. (4)
Answer:

Question 20.
(a) Find the sum of all 3-digit numbers which are multiples of 5. (2)
(b) How many terms of the GP: 3, 3², 3³, …… are needed to give the sum 120? (2)
(c) Find the sum of the first n terms of the series whose nth term is n(n + 3). (2)
Answer:

Reviewing Kerala Syllabus Plus One Computer Science Previous Year Question Papers and Answers Pdf March 2020 helps in understanding answer patterns.

Kerala Plus One Computer Science Previous Year Question Paper March 2020

Time: 2 Hours
Total Score: 60 Marks

Answer any 5 questions from 1 to 6. Each carries 1 score. (5 × 1 = 5)

Question 1.
(1011)₂ = ( ________)₁₀
Answer:
(11)₂

Question 2.
Tangible and visible parts of computer is known as ………………….. .
Answer:
Hardware

Question 3.
The process of correcting errors in program is called ……………………… .
Answer:
debugging

Question 4.
Fundamental building blocks of the program is called ………………………… .
Answer:
Tokens

Question 5.
String function ‘getchar()’ is defined in ………………… header file.
Answer:
cstdio

Question 6.
To append one string to another string, ………………….. function is used.
Answer:
strcat()

Answer any 9 questions from 7 to 18. Each carries 2 scores. (9 × 2 = 18)

Question 7.
Draw the John Von Neumann Architecture for functional units of a computer.
Answer:

Question 8.
State De Morgan’s theorems.
Answer:
De Morgan’s theorem
Demorgan’s first theorem states that \(\overline{X+Y}\) = \(\overline{\mathrm{X}}\) . \(\overline{\mathrm{Y}}\)
ie. the compliment of sum of two variables equals product of their compliments.
The second theorem states that
\(\overline{X . Y}\) = \(\overline{\mathrm{X}}\) + \(\overline{\mathrm{Y}}\)
ie. The compliment of the product of two variables equals the sum of the compliment of that variables.

Question 9.
Write the names of any four CPU registers.
Answer:
Important registers inside a CPU are
a) Accumulator: After performing an operation (arithmetic or logical) the result is stored in the accumulator

b) Memory Address Register(MAR): It stores the address of memory location to which data is either read or written by the processor.

c) Memory Buffer Register (MBR): It stores the data, either to be written to or read from the memory by the processor.

d) Instruction Register(IR): It stores the instructions to be executed by the processor.

e) Program Counter(PC): It stores the address of the next instruction to be executed by the processor.
(Write any four)

Question 10.
Compare entry controlled loop and exit controlled loop.
Answer:

Entry controlled	Exit controlled
Eg. for and while	Do while
The body will be executed only if the test expression becomes true.	But here the body executes at least once even if the condition is false.
Minimum number of execution may be zero	Here it is one

Question 11.
Write the rules followed for naming an identifier.
Answer:
The rules for naming a variable

1. It must be starts with a letter(alphabet)
2. Underscore can be considered as a letter
3. Digits can be used followed by an alphabet
4. White spaces and special characters cannot be used
5. Keywords cannot be used.

Question 12.
Write the logical operators of C++ with its symbols.
Answer:
Logical operators :- Here AND(&&) , OR(||)’are binary operators and NOT(!) is a unary operator. It is used to combine relational operations and it gives either true(1) or false(O).
If x=1 and y=0 then

x && x	x && y	y && x	Y && y
1	0	0	0

Both operands must be true to get a true value in the case of AND (&&) operation.
If x=1 and y=0 then

x || x	x || y	y || x	y || y
1	1	l	0

Either one of the operands must be true to get a true value in the case of OR(||) operation
If x=1 and y=0 then

!x	!y
0	1

Question 13.
What is type promotion in C++?
Answer:
Type promotion- This is also called implicit type conversion. This is performed by C++ compiler internally. C++ converts all the lower sized data type to the highest sized operand.

Question 14.
Write the syntax of ‘for’ statement used in C++.
Answer:

for(initialisation; test expression; updation)
{
body of the loop;
}

Question 15.
Compare Linear search and Binary search.
Answer:

Binary search	Linear search
It requires sorted array	No need of sorted array
Divide and conquer method so no need to visit all the elements	May need to visit all the elements
Takes less time	Takes more time
Suitable for large sized array	Suitable for small sized array.

Question 16.
List any four C++ mathematical functions.
Answer:
abs(), pow(), sqrt(), sin(), cos() (any four)

Question 17.
What is FTTH? Explain its merits.
Answer:
FTTH – Fibre To The Home. Its merits are

• High speed
• High bandwidth
• Less noise
• Long lasting

Question 18.
Describe about search engines with example.
Answer:
Search engines
By using search engines we will get a variety of information. It is a newly developed tool that helped to search the information on the internet more effectively and easily. Search engines are programs that help people to locate information from crores of website on internet using a database that consists of references. Users can interact with the search engine through the home page of the search engine. To get the information about artificial intelligence just type this in the box provided for it and click the search button. Search engines searches by using a particular search algorithm then displays the matching documents or web addresses. Search engine use soft wares called spiders or bots to search documents and their web addresses. Spiders search the internet using the directions given by the search engines and prepare an index and stores it in a database. The searching algorithm searched this database when the users submits a request and create a web page displaying the matching results as hyperlinks.
Eg: Google, Yahoo, Rediff etc.

Answer any 9 questions from 19 to 30. Each carries 3 scores. (9 × 3 = 27)

Question 19.
Prepare a short note about any three generations, of computers.
Answer:
Generations of computers: There are five generations of computers from 16^th century to till date.

Generations of Computers	Period	Component/Technology
First	1940 – 1956	Vacuum tubes
Second	1956 – 1963	Transistors
Third	1964 – 1971	Integrated Circuits (IC)
Fourth	1971 – Present	Microprocessors
Fifth	Present and beyond	Artificial Intelligence

Question 20.
What are universeal gates in Boolean algebra? Draw its symbols with truth tables.
Answer:
Universal gates
By using NAND and NOR gates only we can create other gate hence these gates are called Universal gate.
NAND gate
The output of AND gate is inverted by NOT gate is the NAND gate

In short the NAND gate is as shown below

NOR gate
The output of OR gate is inverted by NOT gate is the NOR gate.

In short the nor gate is shown below

Question 21.
Do the following number conversion:
(i) (34)₈
(ii) (234)₁₀
(iii) (1234)₁₀
Answer:
a) (34)₈ = 3*8¹+4*8⁰ = 24 + 4 = (28)₁₀

b) (234)₁₀
Divide 234 by 2 successively and write down the remainders from bottom to top.
(234)₁₀ = (11101010)₂

c) (1234)₁₀ = ( )₁₆?
Divide 1234 by 16 successively and write down the remainders from bottom to top
(1234)₁₀ = (4D2 )₁₆

Question 22.
Draw the flow chart for printing numbers 1 to 100.
Answer:

Question 23.
What are Literals? Explain its types.
Answer:
Literals (Constants) : Its value does not change during execution
1) Integer literals :- Whole numbers without fractional parts are known as integer literals, its value does not change during execution. There are 3 types decimal, octal and hexadecimal.
Eg. For decimal 100, 150, etc
For octal 0100, 0240, etc
For hexadecimal 0 × 100, 0 × 1 A,etc

2) Float literals A number with fractional parts and its value does not change during execution is called floating point literals.
Eg. 3.14157, 79.78, etc

3) Character literal-: A valid C++ character enclosed in single quotes, its value does not change during execution.
Eg. ‘m’ ‘f’ etc

4) String literal One or more characters enclosed in double quotes is called string constant. A string is automatically appended by a null character(‘\0′)
Eg. “Mary’s”,’’India”,etc.

Question 24.
What is the role of comments in C++ code? Explain its types.
Answer:
Comments are used as user tips means to provide additional information such as developer name, purpose, etc. It is also used for internal documentation.
There are two methods to add comments in C++.
1) Single Line comment(//)- It starts with //, means the string after // in the line is treated as comment. It is not the part of the program.
2) Multi line comment(/* and */)- It starts with /* and ends with */, means the string enclosed between these two even in multiple line is treated as comment.

Question 25.
Write algorithm for bubble sorting.
Answer:
Sorting – Arranging elements of an array in an order(ascending or descending)

Bubble sort :- It is a simple sorting method. In this sorting considering two adjascent elements if it is out of order, the elements are interchanged. After the first iteration the largest(in the case of ascending sorting) or smallest(in the case of descending sorting) will be the end of the array. This process continues.

Question 26.
Differentiate between ‘put()’, ‘write()’ with example.
Answer:

put()	Write()
To print a character on the screen	To print a line of character on the screen
cout.put(’A’);	cout.write(str,len);

Question 27.
Describe the merits of modular programming.
Answer:
Merits of modular programming

• It reduces the size of the program
• Less chance of error occurrence
• Reduces programming complexity
• Improves reusability

Question 28.
Compare two function calling methods in C++.
Answer:
Methods of calling functions
Two types call by value and call by reference.

1. Call by value: In call by value method the copy of the original value is passed to the function, if the function makes any change will not affect the original value.
2. Call by reference: In call by reference method the address of the original value is .passed to the function, if the function makes any change will affect the original value.

Question 29.
What is the need for computer networks?
Answer:
Need for network
The advantages of Networks are given below.

1. Resource sharing: All the computers in a network can share software (programs, data ……………) and
   hardware (printer, scanner, CD drive etc.).
2. Reliability: If one computer fails, the other computer can perform the work without any delay. This is very important for banking, air traffic , control and other application.
3. Price Vs Performance: A main frame computer can be 10 times faster than a PC but it costs thousand
   times a PC. Therefore instead of a main frame 10 personal computers are used with less cost and same performance.
4. Communication Medium: It is a powerful communication medium. We can exchange information between computers in a network.
5. Scalable: This means, System performance can be increased by adding computers to a network.

Question 30.
List the advantages of e-mail.
Answer:
The advantages of email are given below:

1. Speed is high
2. It is cheap
3. We can send email to multiple recipients
4. Incoming message’s can be saved locally
5. It reduces the usage of paper
6. We can access mail box anytime and from any-where.

Part – D

Answer any 2 questions from 31 to 33. Each carries 5 scores. (2 × 5 = 10)

Question 31.
(a) Compare RAM and ROM.
(b) Write a short note about any three output devices.
Answer:
a) The difference between RAM and ROM is given below.

RAM	ROM
1. It is Random Access Memory	1. It is Read only Memory
2. It is Read/Write memory	2. We can’t write but we can only read memory.
3. It is temporary	3. It is permanently stored.
4. It is volatile	4. It Is non volatile
5. RAM is faster	5. It is slower
6. It is used to store data and instructions needed by CPU for processing	6. It contains instructions to check the hardware components, BIOS operations etc.
	7. It is also called firmware.

b)

1. Visual Display Units – After the data processing the result is displayed as soft copy using VDU. Eg. CRT monitor, LCD, LED, OLED. Plasma Panel Etc.
2. Printer – After the data processing the result is displayed as hard copy using Printer or Plotter. Eg. DMP, Inkjet, Laser, Thermal Printer, Etc.
3. Audio Outputs – Speakers are used to produce sound signals from electrical signals.

Question 32.
(a) Differentiate ‘break’ and ‘continue’ statement in table form.
(b) Write the symbol and use fo conditional operator.
(c) Write the example of nested if statement.
Answer:
a)

break	continue
It is used to quit from the loop prematurely	It is used to skip an iteratior and continue the loop with the next value.

b) ?: is the symbol used for conditional operator. It is a ternary operator hence it needs three operands.
Syntax: expression? Value if true: value if false. First evaluates the expression if it is true the second part will be executed otherwise the third part will be executed.

c) An if statement contains another if statement completely then it is called nested if.

if(condition 1)
{
if(condition 2)
{
statement block;
}
}

The statement block will be executed only if both the conditions evaluated are true.

Question 33.
Explain the functions of the following Network devices:
(a) Modem
(b) Switch
(c) Gateway
(d) Multiplex
(e) Router
Answer:
a) Modem – It is used to connect the computer to the internet.
b) Switch – It is used to connect computers(devices) to a network.
c) Gateway – It is used to connect two different networks with different protocols.
d) Multiplexer – It combines the inputs from different channels of a medium and produces one output.
e) Router- It is similar to a bridge, but it can connect two networks with different protocols.

Reviewing Kerala Syllabus Plus One Maths Previous Year Question Papers and Answers Pdf Board Model Paper 2021 helps in understanding answer patterns.

Kerala Plus One Maths Board Model Paper 2021 with Answers

Time: 2 Hours
Total Scores: 60

Answer any 6 questions from 1 to 12. Each carries 3 scores. (6 × 3 = 18)

Question 1.
Let A = {x : x is a prime number less than 10}
(i) Write A in the roster form. (2)
(ii) Number of subsets of A = ____________ (1)
(a) 16
(b) 8
(c) 32
(d) 4
Answer:
(i) A = {2, 3, 5, 7}
(ii) 24 = 16

Question 2.
If A and B are two sets such that n(A) = 100, n(B) = 150 and n(A ∩ B) = 50. Find the following values:
(i) n(A ∪ B) (2)
(ii) n(A – B) (1)
Answer:
(i) n(A ∪ B) = n(A) + n(B) – n(A ∩ B)
= 100 + 150 – 50
= 200
(ii) n(A – B) = n(A) – n(A ∩ B)
= 100 – 50
= 50

Question 3.
Consider the statement p(n): 7ⁿ – 3ⁿ is divisible by 4, n ∈ N
(i) Check whether P(1) is true. (1)
(ii) If P(k) is true. Prove that P(k + 1) is also true. (2)
Answer:
P(n): 7ⁿ – 3ⁿ is divisible by 4
(i) P(1): 7¹ – 3¹ = 7 – 3 = 4, divisible by 4
∴ P(1) is true.
(ii) P(k) = 7^k – 3^k is divisible by 4
ie. 7^k – 3^k = 4m ………(1)
P(k+1): 7^k+1 – 3^k+1
= 7^k . 7 – 3^k. 3
= 7^k . 7 – 7^k. 3 + 7^k . 3 – 3^k. 3
= 7^k (7 – 3) + 3(7^k – 3^k)
= 7^k . 4 + 3 × 4m
= 4(7^k + 3m), divisible by 4
∴ P(k+1) is true whenever P(k) is true.

Question 4.
Using Binomial Theorem expand \(\left(x^2+\frac{3}{x}\right)^5\), x ≠ 0. (3)
Answer:

Question 5.
Finds the middle term in the expansion of \(\left(\frac{x}{3}+9 y\right)^{10}\). (3)
Answer:

Question 6.
In an A.P. 8th term is 16 and 16th term is 48.
(i) Find the common difference of the A.P. (1)
(ii) Find the 25th term of the A.P. (2)
Answer:
(i) a + 7d = 16 …………(1)
a + 15d = 48 …………(2)
(2) – (1) ⇒ 8d = 32
⇒ d = 4
(ii) a + 28 = 16
⇒ a = -12
a₂₅ = a + 24d
= -12 + 24 × 4
= -12 + 96
= 84

Question 7.
(i) The slope of the line joining the points (-2, 6) and (4, 8) is ____________ (1)
(a) 3
(b) \(\frac{1}{3}\)
(c) -3
(d) \(-\frac{1}{3}\)
(ii) If the above line is perpendicular to the line-joining the points (8, 12) and (x, 24) then find the value of ‘x’. (2)
Answer:

Question 8.
(i) A point (x, y, z) is on the XY-plane, then which of the following is always true:
(a) x = 0
(b) y = 0
(c) z = 0
(d) z ≠ 0
(ii) Find the distance between the points A(-2, 3, 5) and B(1, 2, 3). (2)
Answer:
(i) (c) z = 0
(ii) A (-2, 3, 5), B(1, 2, 3)

Question 9.
Find the ratio in which the line segment joining the points (4, 8, 10) and (6, 10, -8) is divided by the YZ plane. (3)
Answer:
Let the YZ plane divide in the ratio k : 1
x = 0

∴ YZ plane divides externally in the ratio 2 : 3.

Question 10.
Consider the parabola y² = 16x.
(i) Length of the jatus rectum of the parabola is ____________ (1)
(a) 4
(b) 16
(c) 8
(d) 32
(ii) Write the co-ordinates of the focus and equation of the directrix of the above parabola. (2)
Answer:
(i) (b) 16
(ii) focus (a, 0) = (4, 0)
Directrix: x = -a
⇒ x = -4
⇒ x + 4 = 0

Question 11.
Evaluate \(\lim _{x \rightarrow 2}\left(\frac{x^5-32}{x^3-8}\right)\). (3)
Answer:

Question 12.
Consider the statement ‘p: If a number is divisible by 10, then it is divisible by 5’. Write the
(i) Negation of the statement (1)
(ii) Converse of the statement (1)
(iii) Contrapositive of the statement (1)
Answer:
(i) Negation: “It is false that if a number is divisible by 10, then it is divisible by 5”.
(ii) Converse: “If a number is divisible by 5, then it is divisible by 10”.
(iii) Contra positive: “If a number is not divisible by 5, then it is not divisible by 10”.

Answer any 6 questions from 13 to 24. Each carries 4 scores. (6 × 4 = 24)

Question 13.
U = {1, 2, 3, 4, 5, 6} be the Universal set and A = {1, 2, 3, 4}, B = {3, 4, 5} are two subsets of U.
(i) Write the sets A’ and B’. (2)
(ii) Verify that A – B = A ∩ B’. (2)
Answer:
(i) A’ = {5, 6}
B’ = {1, 2, 6}
(ii) A – B = {1, 2}
A ∩ B’ = {1, 2, 3, 4} ∩ {1, 2, 6} = {1, 2}
∴ A – B = A ∩ B’

Question 14.
Let A = {-1, 0, 1, 2, 3}, B = {1, 2, 3, 4, 5} be two sets. R be a relation defined from A to B by R = {(x, y) : x + y = 3, x ∈ A, y ∈ B}
(i) Write R in the Roster form. (2)
(ii) Write the domain and range of R. (2)
Answer:
(i) R = {(-1, 4), (0, 3), (1, 2), (2, 1)}
(ii) Domain = {-1, 0, 1, 2}
Range = {4, 3, 2, 1}

Question 15.
(i) Choose one of the possible values of f: R → R, f(x) = sin x from the following values: (1)
(a) \(-\frac{1}{2}\)
(b) 3
(c) -3
(d) 2
(ii) If sin x = \(\frac{3}{5}\), x in the second quadrant. Find the values of cos x and tan x. (3)
Answer:
(i) (a)

(ii) cos x = \(\frac{-4}{5}\)
tan x = \(\frac{-3}{4}\)

Question 16.
Using the principle of Mathematical Induction, prove that for all n ∈ N. (4)
1 + 2 + 3 + …… + n = \(\frac{n(n+1)}{2}\)
Answer:
p(n): 1 + 2 + 3 + …….. + n = \(\frac{n(n+1)}{2}\)
p(1): 1 = \(\frac{1(1+1)}{2}\) = 1
∴ p(1) is true.
Let p(k) be true
(i.e) p(k): 1 + 2 + 3 +….+ k = \(\frac{k(k+1)}{2}\)
We have to prove that p(k + 1) is true
(i.e) p(k + 1): 1 + 2 + 3 +….. + (k + 1) = \(\frac{(k+1)(k+2)}{2}\)
LHS = 1 + 2 + 3 +…..+ k + (k + 1)
= \(\frac{k(k+1)}{2}\) + (k + 1)
= (k + 1) [\(\frac{k}{2}\) + 1]
= \(\frac{(k+1)(k+2)}{2}\)
= RHS
∴ p(k + 1) is true
Hence by P.M.I, p(n) is true for all n ∈ N.

Question 17.
(i) If i = \(\sqrt{-1}\), then i⁴ = ____________ (1)
(i) 1
(b) -1
(c) i
(d) -i
(ii) Write z = \(\frac{2+3 i}{1+2 i}\) in the form a + ib. (3)
Answer:
(i) (a)

Question 18.
(i) Let z = 1 + i, then |z| = ____________ (1)
(a) 1
(b) √2
(c) 2
(d) 0
(ii) Represent the above complex number z in the polar form. (3)
Answer:
(i) (b) √2
(ii) r = |z| = √2
⇒ r cos θ = 1, r sin θ = 1
⇒ cos θ = \(\frac{1}{\sqrt{2}}\), sin θ = \(\frac{1}{\sqrt{2}}\)
⇒ θ = \(\frac{\pi}{4}\)
∴ 1 + i = \(\sqrt{2}\left(\cos \frac{\pi}{4}+i \sin \frac{\pi}{4}\right)\)

Question 19.
How many 4-digit numbers can be formed using the digits 1, 2, 3, 4, and 5, assuming that
(i) Repetition of the digits is allowed. (2)
(ii) Repetition of the digits is not allowed. (2)
Answer:
(i) If digits can be repeated, there are 5 ways each for selecting 4 digits.
∴ By F.P.C. required no. of ways = 5 × 5 × 5 × 5 = 5⁴
(ii) If digits cannot be repeated, required no. of ways = 5 × 4 × 3 × 2 = 120

Question 20.
(i) If ²⁰C₁₂ = ²⁰C_r then one of the possible value of r = ____________ (1)
(a) 9
(b) 8
(c) 11
(d) 10
(ii) A bag contains 7 red balls and 5 white balls. Determine the number of ways in which 3 red balls and 2 white balls can be selected. (3)
Answer:
(i) (b) 8
(ii) Required no. of ways = ⁷C₃ × ⁵C₂
= 35 × 10
= 350

Question 21.
Using method of contradiction prove that ‘√2 is irrational’. (4)
Answer:
Assume √2 is rational
√2 =\(\frac{a}{b}\), where a and b are coprime.
a = √2b
a² = 2b² ………(1)
∴ 2 divides a²
Implies 2 divides a
∴ a = 2c
Substituting in (1)
(2c)² = 2b²
4c² = 2b²
2c² = b²
(i.e) 2 divides b²
Hence 2 divides b which is a contradiction to the fact that a and b are coprime.
Hence our assumption is wrong.
∴ √2 is irrational.

Question 22.
A line cuts off equal intercepts on the coordinate axes and passes through the point (2, 3).
(i) Find the equation of the line. (3)
(ii) Find the slope of the line obtained in (i). (1)
Answer:
(i) Let the equation be \(\frac{x}{a}+\frac{y}{b}\) = 1
Since a = b, \(\frac{x}{a}+\frac{y}{b}\) = 1
(i.e) x + y = a ………..(1)
Since (1) passes through (2, 3),
2 + 3 = a
(i.e) a = 5
∴ Equation of line is x + y = 5
(ii) Slope of line = \(\frac{-1}{1}\) = -1

Question 23.
(i) Write the equation of the ellipse with vertices (±5, 0) and foci (±4, 0). (3)
(ii) Find the length of latus rectum of the above ellipse. (1)
Answer:

Question 24.
Find \(\frac{d y}{d x}\) if y = \(\frac{x^2+1}{x+1}\). (4)
Answer:

Answer any 3 questions from 25 to 30. Each carries 6 scores. (3 × 6 = 18)

Question 25.
Consider the function f: R → R, f(x) = |x – 2|.
(i) The value of f(0) = ____________ (1)
(a) 0
(b) 2
(c) -2
(d) 1
(ii) Draw the graph of the function f. (4)
(iii) Hence write the range of the function f. (1)
Answer:
(i) (b)

(iii) Range = [0, ∞)

Question 26.
(i) Find the value of sin 75°. (3)
(ii) Prove that \(\frac{\sin 5 x+\sin 3 x}{\cos 5 x+\cos 3 x}\) = tan 4x. (3)
Answer:

Question 27.
Solve the following system of inequalities graphically: (6)
x + 2y ≤ 8
2x + y ≥ 8
x > 0, y ≥ 0
Answer:

Question 28.
(i) If the numbers \(\frac{1}{4}\), x, 4 are three consecutive terms of a G.P. Find the value of x. (2)
(ii) Find the sum to n terms of the series 5 + 55 + 555+ ……. (4)
Answer:

Question 29.
Find the variance and standard deviation for the following data:

xi	3	8	13	18	23
fi	7	10	15	10	6

Answer:

Question 30.
In a class of 60 students, 30 opted for NCC, 32 opted for NSS, and 24 opted for both NCC and NSS. One student is selected at random from the class. Find the probability that a student opted for.
(i) NCC (1)
(ii) NCC or NSS (3)
(iii) Neither NCC nor NSS (2)
Answer:
A → Set of students who opted for NCC
B → Set of students who opted for NSS
n(A) = 20, n(B) = 32, n(A ∩ B) = 24

Reviewing Kerala Syllabus Plus One Computer Science Previous Year Question Papers and Answers Pdf Sept 2021 helps in understanding answer patterns.

Kerala Plus One Computer Science Previous Year Question Paper Sept 2021

Time: 2 Hours
Total Score: 60 Marks

Answer any 3 questions from (a) to (e). Each carries 1 score. (3 × 1 = 3)

Question 1.
(a) Difference Engine was developed by __________ .
(b) In a flowchart, the symbol used for processing is __________ .
(c) The data type does not require any memory space is __________ .
(d) Accessing the elements of an array at least once is called __________ .
(e) Variable which can be used anywhere in a program is called __________ .
Answer:
(a) Charles Babbage
(b) Rectangle
(c) Void
(d) Traversal
(e) Global variable

Answer any 11 questions from 2 to 21. Each carries 2 scores. (11 × 2 = 22)

Question 2.
Convert Decimal (28)₁₀ to Binary.
Answer:
(28)₁₀ =(11100)₂

Question 3.
Write the names of any four CPU Registers.
Answer:
Any four from the following
(a) Accumulator
(b) Memory Address Register
(c) Memory Buffer Register
(d) Instruction Register
(e) Program Counter

Question 4.
Expand the following :
(a) USB
(b) HDMI
Answer:
USB – Universal Serial Bus
HDMI – High Definition Multimedia Interface.

Question 5.
Compare Compiler and Interpreter.
Answer:
Compiler: Convert HLL to Machine language. Converting whole program in a single run, Error list is given with line number.
Interpreter: Convert HLL to Machine language. Conversion is done in line by line. Stops at the first error for rectification.

Question 6.
What is meant by Antivirus software ?
Answer:
Antivirus software: It is a tool used to scan computer files for viruses, worms and Trojan horses and cure the infected system. If any fault found it stops the file from running and stores the file in a special area called Quarantine (isolated area) and can be deleted later.

Question 7.
Write an algorithm to find the area of a circle.
Answer:
Step 1 . Start
Step 2 . Input radius, r.
Step 3 . Area= 3.14*r*
Step 4 . Print Area
Step 5 . Stop

Question 8.
What is syntax error ?
Answer:
Syntax error occurs due to violation of rules or syntax of the programming language .It will be displayed during compilation time..

Question 9.
Write down two naming rules followed to form an identifier in C++.
Answer:
Any two.

1. the first character must be a letter or underscore
2. key words not allowed
3. digits can be useful after an alphabet
4. white space or special characters are not allowed
5. it is case sensitive

Question 10.
Write down the datatype modifiers used in C++.
Answer:
short, long, signed and unsigned.

Question 11.
Write the syntax of ‘if’ statement.
Answer:
if statement
First it will check the condition and execute the body only if the
condition is true

Syntax:
if (test expression)
{
statement block ;
}

Question 12.
Describe searching operation in an array.
Answer:
Searching operations

1. Linear search -: In this method each element of the array is compared with the element to be searched starting from the first element.
2. Binary search -: It uses a technique called divide and conquer method. It can be performed only on sorted arrays.

Question 13.
What is the use of function ‘get()’ in C++ ?
Answer:
get() -: It is used to read a character from the keyboard. Eg: cin.get(ch);

Question 14.
Explain the function ‘write()’ in C++ with example.
Answer:
Write() -: It is used to display a string on the monitor.

Question 15.
Write any two merits of Modular Programming.
Answer:
Any 3 points from the following

1. Reduces the size of the program
2. Less chance of errors
3. Reduces programming complexity
4. Improves re usability

Question 16.
What are the arguments of a function ?
Answer:
Arguments are the values passing to the function while it is calling.

Question 17.
Compare strcmp() and strcmpi().
Answer:
strcmp() -: It is used to compare two strings and returns an integer.
strcmpi() -: It is also used to compare two strings andVeturns an integer but it is not case sensitive. It ignores the case.

Question 18.
What is meant by Bandwidth of a Network ?
Answer:
Bandwidth -: The maximum amount of data that can be transmitted by the medium measured in Hertz.

Question 19.
Write a short note on Computer Virus.
Answer:
Virus is a bad program used to corrupt or delete data from our computer.

Question 20.
What is the role of Search Engines in Internet ?
Answer:
Search engine: special programs used to help people to find information in www

Question 21.
Write down the advantages of Email.
Answer:
The advantages are given below

1. Speed is high
2. It is cheap
3. We can send email to multiple recipients
4. Incoming messages can be saved locally
5. It reduces the usage of paper.
6. We can access mail box anytime and from any where.

Answer any 10 questions from 20 to 41. Each carries 3 scores. (10 × 3 = 30)

Question 22.
Describe about any three generations of Computers.
Answer:

Question 23.
What is Sign Magnitude Representation ? Represent (28)₁₀ in Sign Magnitude form.
Answer:
Sign and magnitude representation(SMR) : It is used to represent integers in computer memory. In SMR the MSB is used for representing sign, 1 for -ve and 0 for +ve and the remaining bits for its magnitude.
(28)₁₀ = (11100)₂
Here it is +ve number hence MSB is 0 and insert 3 zeroes before the binary number. So In SMR, (28)₁₀ = (00011100)₂

Question 24.
Write the expansions of the following Graphical Image Formats.
(a) JPEG
(b) GIF
(c) PNG
Answer:
a. JPEG – Joint Photographic Expert Group
b. GIF – Graphic Interchange Format
c. PNG – Portable Network Graphics

Question 25.
Describe any three e-waste disposal methods.
Answer:

1. Reuse -Second hand use or usage after the equipment has been upgraded or modified.
2. Incineration -burn at high temperature
3. Recycle -making new products from old one
4. Land filling-buried in the soil

Question 26.
Write any three functions of Operating System,
Answer:
Major functions of OS

1. Process management
2. Memory management
3. File management
4. Device management

Question 27.
Write any three advantages of Flowchart.
Answer:
Any three
Better communication, Effective analysis, Effective synthesis, Efficient coding.

Question 28.
Draw the flowchart to find the sum and average of three numbers.
Answer:

Question 29.
Write any three escape sequence with its function.
Answer:

Escape sequence	Function
\a	Audible sound
\b	Back space
\n	New line
\r	Carriage return
\t	Horizontal tab

Question 30.
Describe about Relational Operators in C++.
Answer:
Relational Operators – There are six operators, It is a binary operator and it returns result as Boolean value.

• < less than
• <= less than or equal to
• > greater than
• >= greater than or equal to
• == equal to
• != not equal to
  Ifx=10andy=20then

Operation	x<y	x<=y	x>y	x>=y	x==y	x!=y
Result	true	true	false	false	false	true

Question 31.
Write the structure of a C++program.
Answer:

# include <iostream> /#include<header file>
using namespace std ;
int main ()
{
statements
}

Question 32.
Describe the different types of comments used in C++ with example.
Answer:
Comments in C++ are used for giving internal documentation (user tips). It will not be executed by the compiler.
Single line comment //
Multiline comment /* ………………….. */

Question 33.
Explain the Conditional Operator with example.
Answer:
Conditional(Ternary) operator condition?
Value if true : Value if false;
First the condition is evaluated , if it is true the second part will be executed otherwise the third part will be executed.
Eg:
int max;
max=10<20?20:10;
Here max will be 20.

Question 34.
Write down an example for multiple branching switch statement.
Answer:

switch(n)
{
case 1: cout<<“Sunday”;break;
case 2: cout<<“Monday”;break;
case 3: cout<<“Tuesday”; break;
case 4: cout<<“Wednesday”;break;
case 5: cout<<“Thursday”;break;
case 6: cout<<“Friday”;break;
case 7: cout<<“Saturday”;break;
default: cout<<“Invalid”;
}

Question 35.
What is meant by Index in an array ? Explain its role in accessing array elements.
Answer:
In an array the first or second or third etc. can be distinguished by using the index (subscript). The index of first element is 0.

Question 36.
Explain any array sorting algorithm.
Answer:
Sorting – Arranging elements of an array in an order (ascending or descending)
1. Bubble sortIt is a simple sorting method. In this sorting considering two adjascent elements if it is out of order, the elements are interchanged. After the first iteration the largest(in the case of ascending sorting) or smallest(in the case of descending sorting) will be the end of the array. This process continues.

2. Selection sortIn selection sort the array is divided into two parts, the sorted part and unsorted part. First smallest element in the unsorted part is searched and exchanged with the first element. Now there is 2 parts sorted part and unsorted part. This process continues

Question 37.
Explain User Defined Functions.
Answer:
User defined functions are functions created by the user to solve a specific tasks. Its syntax is given below.

Return_type Function_name(argument list)
{
Body of the function.
}

Question 38.
Compare Call by Value and Call by Reference.
Answer:

1. Call by value -: In this method the copy of the original value is passed to the function, if the function makes any change will not affect the original value.
2. Call by reference-: In this method the address of the original value is passed to the function, if the function makes any change will affect the original value.

Question 39.
Explain any three needs of Computer Network.
Answer:
Any three from the following :

1. Resource sharing
2. Reliability
3. Price / Performance ratio
4. Communication
5. Scalability

Question 40.
Write the full forms of
(a) WiFi
(b) MAC
(c) IP
Answer:
(a) WiFi – Wireless Fidelity
(b) MAC – Media Access Control
(c) IP – Internet Protocol

Question 41.
What is meant by Phishing ?
Answer:
Phishing(Fishing) It is an attempt to get others information such as usernames, passwords, bank a/c details etc. by acting as the authorised website. Phishing websites have URLs and home pages similar to their original ones and mislead others.

Answer only 1 questions from 42 to 44. carries 5 scores. (1 × 5 = 5)

Question 42.
Describe Logic Gates OR, AND, NOT with Symbol and Truth Table.
Answer:
a. The OR gate
It gives 1 either one of the operands is 1.

b. The AND gate
It gives 1 if and only if both operands are 1.

c. The NOT gate
It produces the vice versa.

Question 43.
Compare for, while and do-while loops.
Answer:
Loop statement – control statements used to execute a block of statements repeatedly

• for
• while
• do... while
for (initialisation expression ; test expression ; update expression)
{
Body of the loop ;
}
while loop
Initialisation expression;
while (test expression)
{
Body of the loop ;
Update expression;
}
do ........... while loop
initialisation;
do
{
body of the loop;
update statement;
}
while (test expression);

Question 44.
Explain different Network Topologies with diagrams.
Answer:
• Bus topology
• Star topology
• Ring topology
• Mesh topology

Any one from the following
J Bus topology – In bus topology all the nodes are connected to a main cable called bus. A small device called a terminator is attached to each end of the bus.

Star topology – In star topology each node is directly connected to a hub switch.

Ring topology – In ring topology all nodes are connected using a cable that shapes like a ring or circle Data travels only in one direction in a ring.

Mesh topology – In mesh topology every node is connected to other nodes. There will be more than one path between two nodes.

 

Reviewing Kerala Syllabus Plus One Maths Previous Year Question Papers and Answers Pdf Board Model Paper 2022 helps in understanding answer patterns.

Kerala Plus One Maths Board Model Paper 2022 with Answers

Time: 2 Hours
Total Scores: 60

Answer any 6 questions from 1 to 8. Each carries 3 scores. (6 × 3 = 18)

Question 1.
(a) If a set A has 2 elements, then the number of subsets of A is ___________________ (1)
(i) 2
(ii) 4
(iii) 6
(iv) 8
(b) Write all subsets of {1, 2}. (1)
(c) Write the interval (6, 12] in set-builder form. (1)
Answer:
(a) (ii) 4
(b) {1}, {2}, {1, 2},
(c) {x : x ∈ R,6 < x ≤ 12}

Question 2.
(a) \(\frac{\pi}{4}\) radian = _____________ degree. (1)
(b) If sin x = \(\frac{3}{5}\), x lies in the second quadrant, find the values of cos x and tan x. (2)
Answer:
(a) 45

Question 3.
(a) Write the first four terms of the sequence whose nth term is a_n = 5n + 1. (1)
(b) Find the sum of the first n terms of the above sequence. (2)
Answer:
(a) a_n = 5n + 1
a₁ = -5 + 1 = 6
a₂ = 10 + 1 = 11
a₃ = 15 + 1 = 16
a₄ = 20 + 1 = 21
∴ First four terms are 6, 11, 16, 21
(b) a = 6, d = 5

Question 4.
(a) Find the slope of the line passing through the points (2, 1) and (4, 5). (1)
(b) Find the value of x for which the points (x, -1), (2, 1) and (4, 5) are collinear. (2)
Answer:
(a) Slope m = \(\frac{5-1}{4-2}=\frac{4}{2}\) = 2
(b) Given A(x, -1), B(2, 1), C(4, 5)
Slope of AB = Slope of BC

Question 5.
Find the equation of the circles with radius 5 whose centres lie on the x-axis and passing through the point (2, 3). (3)
Answer:

Let C(h, 0) be the centre.
∴ CP = 5
⇒ \(\sqrt{(h-2)^2+(3-0)^2}\) = 5
⇒ \(\sqrt{(h-2)^2+9}\) = 5
⇒ (h – 2)² + 9 = 25
⇒ (h – 2)² = 16
⇒ h – 2 = ±4
⇒ h – 2 = 4 or h – 2 = -4
⇒ h = 6 or h = -2
If the centre is (6, 0), the equation of a circle is (x – 6)² + y² = 25
If the centre is (-2, 0), the equation of a circle is (x + 2)² + y² = 25

Question 6.
(a) Coordinate planes divide the space into octants. (1)
(b) Find the distance between the points (-1, 3, -4) and (1, -3, 4). (2)
Answer:
(a) 8
(b) Given A(-1, 3, -4), B(1, -3, 4)
AB = \(\sqrt{(1+1)^2+(-3-3)^2+(4+4)^2}\)
= \(\sqrt{4+36+64}\)
= \(\sqrt{104}\)

Question 7.
Evaluate:
(a) \({Lt}_{x \rightarrow 4} \frac{4 x+3}{x-2}\) (1)
(b) \({Lt}_{x \rightarrow 1} \frac{x^3-1}{x^2-1}\) (2)
Answer:

Question 8.
(a) Write the negation of the statement ‘√7 is rational’. (1)
(b) Write the contrapositive and converse of the statement ‘If a number n is even, then n² is even’. (2)
Answer:
(a) It is not the case that √7 is rational.
(b) Contra positive: ‘If n² is not even then n is not even’.
Converse: ‘If n² is even then n is even’.

Answer any 6 questions from 9 to 17. Each carries 4 scores. (6 × 4 = 24)

Question 9.
(a) If A and B are two sets such that A ⊂ B, then A ∪ B = _____________ (1)
(b) If U = {1, 2, 3, 4, 5, 6, 7, 8, 9}, A = {2, 4, 6, 8} and B = {2, 3, 5, 7}, find:
(i) A’ and B’. (1)
(ii) A ∪ B (1)
(iii) Verify that (A ∪ B)’ = A’ ∩ B’ (1)
Answer:
(a) B
(b) (i) A’ = {1, 3, 5, 7, 9}
B’ = {1, 4, 6, 8, 9}
(ii) A ∪ B = {2, 3, 4, 5, 6, 7, 8}
(iii) (A ∪ B)’ = {1, 9}
A’ ∩ B’ = {1, 9}
∴ (A ∪ B)’ = A’ ∩ B’

Question 10.
(a) Let A = {1, 2, 3, 4,…, 14}, define a relation R from A to A by R = {(x, y) : y = 3x, wherex, y ∈ A}. Write R in roster form. Write down the domain and range of R. (3)
(b) A function f is defined by f(x) = 2x – 5. Find the value of f(0). (1)
Answer:
(a) R = {(1, 3), (2, 6), (3, 9), (4, 12)}
Domain = {1, 2, 3, 4}
Range = {3, 6, 9, 12}
(b) f(x) = 2x – 5
f(0) = 2(0) – 5 = 0 – 5 = -5

Question 11.
Consider the statement
P(n): 1 + 3 + 3² + …… + 3^(n-1) = \(\frac{3^n-1}{2}\)
(a) Show that P(1) is true. (1)
(b) Prove by the principle of Mathematical Induction that P(n) is true for all n ∈ N. (3)
Answer:
(a) P(1): 1 = \(\frac{3^{\prime}-1}{2}=\frac{3-1}{2}=\frac{2}{2}\) = 1
∴ P(1) is true.
(b) Let us assume thatp(n) is true for n = k
(i.e) P(k): 1 + 3 + 3² + ……. + 3^k-1 = \(\frac{3^k-1}{2}\)
Now we have to prove that P(n) is true for n = k + 1

P(k + 1) is true.
∴ By the principle of Mathematical induction, P(n) is true for all n ∈ N.

Question 12.
(a) Evaluate \(\frac{7!}{5!}\). (1)
(b) How many 4 digit numbers can be formed using the digits 1 to 9 if repetition of digits is not allowed? (2)
(c) ¹⁷C₁₇ = __________ (1)
Answer:
(a) \(\frac{7!}{5!}=\frac{7 \times 6 \times 5!}{5!}\) = 42
(b) There are 9 ways to select units, 8 ways to select 10’s place, 7 ways to select 100’s place, and 6 ways to select 1000’s place.
∴ By fundamental principle of counting, required number of ways = 9 × 8 × 7 × 6 = 3024
(c) ¹⁷C₁₇ = 1

Question 13.
(a) The number of terms in the expansion of (a + b)⁴ is ______________ (1)
(b) Expand \(\left(x^2+\frac{3}{x}\right)^4\), x ≠ 0. (3)
Answer:
(a) 5

Question 14.
The sum of the first three terms of a Geometric Progression is \(\frac{39}{10}\) and their product is 1. Find the common ratio and the terms of the Geometric Progression. (4)
Answer:
Let the terms be \(\frac{a}{r}\), a, ar
∴ \(\frac{a}{r}\) + a + ar = \(\frac{39}{10}\) ……….(1)
\(\frac{a}{r}\) . a . ar = 1 …….(2)
⇒ a³ = 1
⇒ a = 1
Substituting this in equation (1),
\(\frac{1}{r}\) + 1 + r = \(\frac{39}{10}\)
Multiplying throughout by ’10r’
⇒ 10 + 10r + 10r² = 39r
⇒ 10r² – 29r + 10 = 0
⇒ 10r² – 25r – 4r + 10 = 0
⇒ 5r(2r – 5) – 2(2r – 5) = 0
⇒ (2r – 5)(5r – 2) = 0
⇒ r = \(\frac{5}{2}\) or r = \(\frac{2}{5}\)
If a = 1, r = \(\frac{5}{2}\) terms are \(\frac{2}{5}\), 1, \(\frac{5}{2}\)
If a = 1, r = \(\frac{2}{5}\) terms are \(\frac{5}{2}\), 1, \(\frac{2}{5}\)

Question 15.
(a) Write the equation of the x-axis. (1)
(b) Equation of a line is 3x + 2y – 12 = 0. Find its
(i) Slope (1)
(ii) x and y intercepts. (2)
Answer:
(a) y = 0
(b) (i) Slope = \(\frac{-A}{B}=\frac{-3}{2}\)
(ii) x intercept = \(\frac{-C}{A}=\frac{12}{3}\) = 4
y intercept = \(\frac{-C}{B}=\frac{12}{2}\) = 6

Question 16.
Find the coordinates of the foci. The eccentricity and the length of the latus rectum of the ellipse \(\frac{x^2}{16}+\frac{y^2}{9}\) = 1. (4)
Answer:

Question 17.
One card is drawn from a well shuffled deck of 52 cards. If each outcome is equally likely, calculate the probability that the card will be
(i) a diamond (1)
(ii) not an ace (2)
(iii) a black card (1)
Answer:

Answer any 3 questions from 18 to 22. Each carries 6 scores. (3 × 6 = 18)

Question 18.
(a) Prove that \(\frac{\tan \left(\frac{\pi}{4}+x\right)}{\tan \left(\frac{\pi}{4}-x\right)}=\left(\frac{1+\tan x}{1-\tan x}\right)^2\). (3)
(b) Find the general solution for the equation cos 3x + cos x – cos 2x = 0. (3)
Answer:

(b) cos 3x + cos x – cos 2x = 0
⇒ 2 cos 2x . cos x – cos 2x = 0
⇒ cos 2x (2 cos x – 1) = 0
⇒ cos2x = 0 or 2 cos x – 1 = 0
Now, cos 2x = 0
⇒ 2x = (2n + 1)\(\frac{\pi}{2}\)
⇒ x = (2n + 1)\(\frac{\pi}{4}\); n ∈ Z
and, 2 cos x – 1 = 0
2 cos x = 1
cos x = \(\frac{1}{2}\)
cos x = cos\(\frac{\pi}{3}\)
x = 2nπ ± \(\frac{\pi}{3}\); n ∈ Z

Question 19.
(a) The value of i⁴ is _____________ (1)
(b) Find the multiplicative inverse of 1 – i in a + ib form. (2)
(c) Find the polar form of 1 – i. (3)
Answer:
(a) 1
(b) Let z = 1 – i

Question 20.
Solve the system of inequalities graphically. (6)
x + 2y ≤ 8
2x + y ≤ 8
x ≥ 0, y ≥ 0
Answer:

Question 21.
(a) Find the derivative of sin x from first principle. (3)
(b) Find the derivative of 5 sin x – 6 cos x + 7. (3)
Answer:

(b) f(x) = 5 sin x – 6 cos x + 7
f'(x) = 5 cos x + 6 sin x

Question 22.
Consider the following data:

Classes	0 – 10	10 – 20	20 – 30	30 – 40	40 – 50
Frequency	5	8	15	16	6

Find:
(i) Mean (2)
(ii) Variance and standard deviation. (4)
Answer:

Reviewing Kerala Syllabus Plus One Computer Science Previous Year Question Papers and Answers Pdf June 2022 helps in understanding answer patterns.

Kerala Plus One Computer Science Previous Year Question Paper June 2022

Time: 2 Hours
Total Score: 60 Marks

Answer any five questions from 1 to 7. Each carries 1 score. (5 × 1 = 5)

Question 1.
Who is known as the Father of Computer Science as well as Artificial Intelligence?
Answer:
Alan Turing

Question 2.
Write an example for free and open Source Software.
Answer:
GNU Linux/GIMP/Open Office etc.

Question 3.
Write the ternary operator in C++.
Answer:
(Ternary operator needs 3 operands) Conditional operator (?:) Eg. max=x>y?x:y;

Question 4.
In C++ _________ character is known as the string terminator.
Answer:
Null character(\0)

Question 5.
The process of calling a function by itself is known as _________ .
Answer:
Recursive function

Question 6.
To include a mathematical built in functions in a C++ program, we should include _________ header file.
Answer:
cmath

Question 7.
Write the name of a network protocol.
Answer:
TCP/IP/ HTTP/ HTTPS/FTP/SFTP/SMTP/IMAP/ POP…(Any One)

Answer any 9 questions from 8 to 19. Each carries 2 scores. (9 × 2 = 18)

Question 8.
(507)₈ =(__________)₂ = (____________)₁₆
Answer:
Conversion from octal to binary-: Write down the 3 bit binary equivalent of each number.
So (507)₈ = (101 000111 )₂

Conversion from binary to hexadecimal:- Divide the number into groups of four bits (Starting from the right) then insert necessary zeroes in the left side and write the corresponding hexa equivalent.
(101 000 111)₂ = ()₁₆
0001->1 0100->4 0111->7
So the answer is 147
So (507)₈ = (101 000 111 )₂ = (147)₁₆

Question 9.
Differentiate between FtAM and ROM RAM
Answer:

RAM	ROM
Read and write memory (Just like our note book)	Read only memory (Just like our text book)
Faster	Slower
Volatile	Non volatile
Stores programs and data	Stores BOOT programs

Question 10.
Write the names of registers inside the CPU.
Answer:

• Accumulator
• Memory Address Register
• Memory Buffer Register
• Program Counter
• Instruction Register

Question 11.
What are the major functions of an operating system?
Answer:
Major functions are memory management, Process management, File management and device management.

Question 12.
Distinguish between Syntax error and Logical Error.
Answer:
When the programmer violates the syntactical rules then syntax error occurs and it is displayed after compilation. Eg. not using comma for multiple variable declaration, int x y z instead of int x, y, z; If the programmer makes a logical mistake then logical error occurs but it is not displayed at the time of compilation and may not get the correct answer. To find the product (*) of x and y, using + instead of *.

Question 13.
Differentiate between character and string literals.
Answer:

Character literal	String literal
Both are constants
Single character enclosed in single quotes	Multiple character enclosed in double quotes
Eg. ‘m’ or ‘f or ‘t’	Eg. “BVM HSS Kalparamba”

Question 14.
Write a short note on any two jump statements used in C++.
Answer:
The execution of a program is sequential but we can change this sequential manner by using jump statements. The jump statements are
1. goto statement:- By using goto we can transfer the control anywhere in the program without any condition. The syntax is goto label;

Eg.
#include<iostream>
using namespace std;
intmain()
{
float a,b;
cout<<"Enter 2 numbers";
cin>>a>>b;
if(b==0)
goto end;
cout<<"The quotient is "<<a/b;
return 0;
end:cout<<"Division by zero error";
}

2. break statement:- It is used to skip over a part of the code i.e. we can premature exit from a loop such as while, do-while, for or switch.

Syntax :
while (expression)
{
if (condition)
break;
}
Eg.
#include<iostream>
using namespace std;
main()
{
int i=1;
while(i<10)
{
cout<<i<<endl;
if(i==5)
break;
i++;
}
}
The output is
1
2
3
4
5

3. continue statement:- It bypasses one iteration of the loop.

Syntax :
while (expression)
{
if (condition)
break;
}
Eg.
#include<iostream>
using namespace std;
main()
{
int i=0;
while(i<10)
{
i++;
if(i==5) continue;
cout<<i<<endl;
}
}
The output is
1
2
3
4
6
7
8
9
10

4. exit(0) function:- It is used to terminate the program. For this the header file cstdlib must be included.

Question 15.
Compare switch and if else if ladder statements used in C++.
Answer:

else if ladder	switch
Evaluate condition with any relational or logical expression	Evaluate expression with equality operator(==) only
It can handle floating values	It cannot(only integer or character)
If the test expression contains more variable If else is used	It cannot
When no match is found then else block is executed	Here default block is executed
Program control automatically goes out	Sometimes break statement is needed

Question 16.
Write C++ statement to declare an array which can store 5 integer values and explain about the memory allocation of the array.
Answer:
int n[5]; An integer requires 4 bytes so 5*4=20 bytes of memory is allocated for this array.

Question 17.
Differentiate between linear and binary search algorithms.
Answer:

Linear Search	Binary Search
The elements need not be in an order	The elements must be in a sorted order
It may be visit all the elements	Never visit all the elements
Suitable for small sized array	Suitable for large sized array
Slower- Takes more time	Faster- Takes less time

Question 18.
Briefly explain about any two string built in function in C++.
Answer:
String functions
a) strlen()- to find the number of characters in a string(i.e. string length).
Syntax: strlen(string);
Eg. cout<<strlen(“Computer”); It prints 8.

b) strcpy()- It is used to copy second string into first string.
Syntax: strcpy(string 1, string2);
Eg. strcpy(str,”BVM HSS”);
cout<<str; It prints BVM HSS.

c) strcat()- It is used to concatenate second string into first one.
Syntax: strcat(string1,string2)
Eg.strcpy(str1,’’Hello”);
strcpy(str2,” World”);
strcat(str1 ,str2);
cout<<str1; It displays the concatenated string
“Hello World”

Question 19.
Write a short note about the following C++ statement: int sum(int.int);
Answer:
int sum(int.int); -: It is a function proto type ; This tells the compiler that there is a function namely sum with two integer arguments and its return type is also an integer. It is compulsory when the function definition is after the main function.

Answer any 9 questions from 20 to 32. Each carries 3 scores. (9 × 3 = 27)

Question 20.
Compare First and Second Generations of Computers.
Answer:

	First	Second
Component	Vacuum Tubes	Transistor
Period	1940 – 56	1956 – 63
Size	Larger	Smaller
Speed	Slower	Faster

Question 21.
Find the 1 ‘s Compliment and 2’s Compliment form of(-78)₁₀.
Answer:
+78 in 8 bits is (01001110)₂
To find 1’s complement change all ones to Zeroes and vice versa.
So -78 in 1’s complement form is 10110001 To find 2’ complement, add 1 to the 1 ’s complement. So-78 in 2’s complement form is 10110001 + 1 =10110010 So the answer is (10110010)₂

Question 22.
What is e-Waste? Briefly explain about any two e-Waste disposal methods.
Answer:
e-Waste(electronic waste): It refers to the mal functioning electronic products such as faulty computers, mobile phones, tv sets, toys, CFL etc.

e-Waste disposal methods
a) Reuse: Reusability has an important role of e-Waste management and can reduce the volume of e-Waste
b) Incineration: It is the process of burning e Waste at high temperature in a chimney
c) Recycling of e-Waste: It is the process of making new products from this e-Waste.
d) Land filling: It is used to level pits and cover by thick layer of soil.

Question 23.
What are the different phases in programming?
Answer:

1. Problem identification
2. Algorithm and flowchart
3. Coding
4. Translation
5. Debugging
6. Execution
7. Documentation

Question 24.
Identify the invalid identifiers from the following and write reason for that:
A20bc, if, 5 sum, adm_no, student age, classno
Answer:

1. If – It is a keyword
2. 5sum – It can’t start with a digit
3. student age-Space cannot be used

Question 25.
Briefly explain about the structure of a C++ Program.
Answer:

#include<iostream>
using namespace std;
intmain()
{
Body of the program
return 0;
}

Question 26.
Write C++ code fragments to print the numbers from 1 to 10 using an exit or enter controlled loop.
Answer:
for(i=1;i<=10;i++)
cout<<i<<endl;

Question 27.
Write the steps to sort the following numbers stored in an array using bubble sort algorithm: 3, 7, 1, 2, 6
Answer:

3

7

1

2

6

Step 1 : Compare 3 and 7, here 7 is the bigger then no change

3

7

1

2

6

Step 2 : Compare 7 and 1, here 7 is the bigger then swap 7 and 1 so we will get as follows

3

1

7

2

6

Step 3 : Compare 7 and 2, here 7 is the bigger then swap 7 and 2 so we will get as follows

3

1

2

7

6

Step 4 : Compare 7 and 6, here 7 is the bigger then swap 7 and 6 so we will get as follows

3

1

2

6

7

After the first phase the largest number is on the right side, Similarly do the remaining

Step 5 : Compare 3 and 1 . here 3 is the bigger then swap 3 and 1 so we will get as follows

1

3

2

6

7

Step 6 : Compare 3 and 2, here 3 is the bigger then swap 3 and 2 so we will get as follows

1

2

3

6

7

Step 7 : Compare 3 and 6, here 6 is the bigger then no change so we will get as follows

1

2

3

6

7

Question 28.
Explain about any three stream functions used in C++.
Answer:
Stream functions for I / O operations :
Somefunctions that are available in the header file iostream.h to perform I / O operations on character and strings(stream of characters). It transfers streams of bytes between memory and objects. Keyboard and monitor are considered as the objects in C++.

Input functions: The input functions like get( )(to read a character from the keyboard) and getline() (to read a line of characters from the keyboard) is used with cin and dot(.) operator.

Eg.
#include<iostream>
using namespace std;
intmain()
{
char str[80],ch=’z’;
cout<<“enter a string that end with z:”;
cin.getline(str,80,ch);
cout<<str;
}

If you run the program you will get the prompt as follows
Enter a string that end with z: Hi I am Jobi. I am a teacherz.My school is BVM HSS
The output will be displayed as follows and the string after ‘z’ will be truncated.
Hi I am Jobi. I am a teacher

Output function: The outputt functions like put() (to print a character on the screen) and write() (to print a line of characters on the screen) is used with cout and dot(.) operator.

Question 29.
Distinguish between Call by value and Call by reference methods.
Answer:

Call by Value	Call by Reference
Ordinary variables are used as formal parameter	Reference variables are used as formal parameters
A copy of the original value is passed	The original value is passed
Any change made by the function will not affect the original value	Any change made by the function will affect the original value
Separate memory location is needed for actual and formal variables	Memory of actual arguments is shared by formal arguments.

Question 30.
Prepare a short note about the following:
a) Optical fibre cable
b) NIC
c) Gateway (1 + 1 + 1)
Answer:
a) Optical Fibre Cable – These are made of glass fibres that are enclosed in a plastic jacket. It uses light signals instead of electrical signals. The light sources are LED or ILD.

b) NIC – Network interface card, It enables a computer to connect to a network and transmit information.

c) Gateway – It is used to connect two different networks with different protocols.

Question 31.
What are the major classifications of Social Media?
Answer:
Major classifications are

1. Internet forums
2. Social blogs
3. Micro blogs
4. Social net works
5. Content communities
6. Wikis

Question 32.
Write a short note about:
a) Fibre to Home (FTTH)
b) Phishing
c) Android Operating system (1 + 1 + 1)
Answer:
a) Fibre to Home(FTTH): This uses optical fibres hence the speed is very high. Special type modem is required.

b) Phishing (Fishing): It is an attempt to get others information such as usenames, passwords, bank a/c details etc by acting as the authorized website. Phishing websites have URLs and home pages similar to their original ones and mislead others, it is called spooling.

c) Android Operating System: It is Linux based OS? for touch screen devices such as smart phones and tablets. It was developed by Android Inc. by Andy Rubin and his friends. Now it is owned by Google.

Answer any 2 questions from 33 to 36. Each carries 5 scores. (2 × 5 = 10)

Question 33.
a) Draw the logic circuit for the Boolean expression A.B + C.D (3)
b) Find the Dual of the Boolean expression A + 0 = A (2)
Answer:

b) A.1=A

Question 34.
a) What are the advantages of flow charts? (2)
b) Draw a flowchart to check whether the number is even or odd. (3)
Answer:
a) The advantages of flow charts are as follows
a) Better communication
b) Effective analysis
c) Effective synthesis
d) Effective coding

Question 35.
a) Briefly explain about the Fundamental data types used in C++. (3)
b) What are the data type modifiers in C++? (2)
Answer:
Fundamental data types: It is also called built in data type. They are int, char, float, double and void

i) int data type-: It is used to store whole numbers without fractional (decimal point) part. It can be either negative or positive. It consumes 4 bytes (32 bits) of memory.i.e. 2³² numbers. That is 2³¹ negative numbers and 2³¹ positive numbers (0 is considered as +ve ) So a total of 2³² numbers. We can store a number in between -2³¹ to + 2³¹-1.

ii) char data type :- Any symbol from the key board, eg. ‘A’, ‘?’, ‘9’,…. It consumes one byte ( 8 bits) of memory. It is internally treated as integers, i.e. 2⁸ = 256 characters. Each character is having a ASCII code, ‘a’ is having ASCII code 97 and zero is having ASCII code 48.

iii) float data type:- It is used to store real numbers i.e. the numbers with decimal point. It uses 4 bytes(32 bits) of memory. Eg. 67.89, 89.9 E-15.

iv) double data type:- It is used to store very large real numbers. It uses 8 bytes(64 bits) of memory,

v) void data type void means nothing. It is used to represent a function returns nothing,

b) Type modifiers are long, short, signed and unsigned.

Question 36.
Write the names of 4 topologies and explain about two topologies.
Answer:
Network topologies: Physical or logical arrangement of computers on a network is called structure or topology. It is the geometrical arrangement of computers in a network. The major topologies developed are star, bus, ring, tree and mesh.

1) Star Topology: A star topology has a server all other computers are connected to it. If computer / A wants to transmit a message to computer B. Then computer A/irst transmit the message to the server then the server retransmits the message to the computer B. That means all the messages are transmitted through the server. Advantages are add or remove workstations to a star network is easy and the failure of a workstation will not , effect the other. The disadvantage is that if the server fails the entire network will fail.

2) Bus Topology: Here all the computers are attached to a single cable called bus. Here one computer transmits all other computers listen. Therefore it is called broadcast bus. The transmission from any station will travel in both the direction. The connected computers can hear the message and check whether it is for them or not.

Advantages are add or remove computer is very easy. It requires less cable length and the installation cost is less. Disadvantage is fault detection is very difficult because of no central computer.

3) Ring Topology : Here, all the computers are cbnnected in the shape of a ring and it is s. closed loop. Here also there is no central computer. Here a computer ti^nsmits a message, which is tagged along with its destination computer’s address. The message travels in one direction and each node check whether the message is for them. If not, it passes to the next node.

It requires only short cable length. If a single node fails, at least a portion of the network will fail. To add a node is very difficult.

4) Hybrid Topology: It is a combination of any two or more network topologies. Tree topology and mesh topology can be considered as hybrid topology.
a) Tree Topology : The structure of a tree topology is the shape of an inverted tree with a central node and branches as nodes. It is a variation of bus topology. The data transmission takes place in the way as in bus topology. The disadvantage is that if one node fails, the entire portion will fail.

b) Mesh Topology: In this topology each node is connected to more than one node. It is just like a mesh (net). There are multiple paths between computers. If one path fails, we a transmit data through another path.