Kerala Plus One Computer Science Question Paper Sept 2021 with Answers

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.