Kerala Plus One Computer Science Question Paper March 2020 with Answers

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.