Kerala Plus One Computer Science Board Model Paper 2020 with Answers

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

Kerala Plus One Computer Science Board Model Paper 2020 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 among the following is an invalid number?
a) (10110)₁₀
b) (769)₈
c) (ABC)₁₆
d) (111)₂
Answer:
b) (769)₈ because 9 is not allowed in octal number system.

Question 2.
Which among the following is the fastest memory in a computer?
a) Registers
b) Cache
c) Hard Disk
d) RAM
Answer:
a) Registers

Question 3.
Which among the following is not a keyword in C++?
a) float
b) for
c) cin
d) int
Answer:
c) cin. It is not a keyword.

Question 4.
The conditional operator (?:) inC++ is a
a) Unary operator
b) Binary operator
c) Ternary operator
d) Logical Operator
Answer:
c) Ternary operator

Question 5.
Write equivalent C++ statement for the Mathematical equation z = x^y.
Answer:
z = pow(x, y);

Question 6.
SIM cards are used in mobile phones. Write the full form of SIM.
Answer:
Subscribers Identification Module

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

Question 7.
Match the following:

a) First generation computers	1) Microprocessor
b) Second generation computers	2) Vaccum Tube
c) Third generation computers	3) Integrated Circuit
d) Fourth generation computers	4) Transister

Answer:

a) First generation computers	2) Vaccum Tube
b) Second generation computers	4) Transister
c) Third generation computers	3) Integrated Circuit
d) Fourth generation computers	1) Microprocessor

Question 8.
Convert the hexadecimal number (A2D)₁₆ into octal equivalent.
Answer:
It first convert it into binary and then convert it into octal.

Step 1: First convert it into binary for this write down the corresponding binary equivalent of each symbol in 4 digits
(A2D)₁₆ = (101000101101)₂

Step 2: Then convert this into octal for this divide the number into groups of 3 bits and write down the corresponding octal equivalent.

Hence the answer is (5055)₈

Question 9.
Write four complementory approaches to promote green computing.
Answer:
Green Design, Green Manufacturing, Green Use and Green Production.

Question 10.
Write short notes about the methods of program documentation.
Answer:
There are two types of documentation internal and external.

1. Internal documentation- Writing comments in source code such as including name of the programmer, purpose of the code etc. This user tips will help in debugging and future modifications.
2. External documentation – It includes preparation of user manual and system manual.

Question 11.
Identify tokens in the following C++ statement and write in which type they belong to. float x = 3.14;
Answer:
float – Keyword.
x – Identifier.
= – Operator.
3.14 – Literal.
; – Punctuator.

Question 12.
Write use of data type modifiers in C++. Give two examples of data type modifiers.
Answer:
By using data type modifiers we can change the size, range and precision of data types.
They are signed, unsigned, long and short.

Question 13.
Comments are useful to enhance readability and understandability of a program. What are the methods of writing comments in a C++ program?
Answer:
There are two methods to add comments in C++.

1. Single Line comment(//)- It starts with II, means the string after // in the line is treated as comment. It is not the part of the program
2. Multi line comments(/* and */)- It starts with /* and ends with */, means the string enclosed between these two even in multiple line is treated as comment.

Question 14.
Write syntax of it …… else statement in C++.
Answer:

if(Test expression)
{
Statement block 1;
}
else
{
Statement block2;
}

Question 15.
Compare binary search method with linear search method and write advantage of binary search method.
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.
Write built – in functions in C++ for the following:
a) To get number of character in a string.
b) To append one string to another string.
a) To find absolute value of an integer.
b) To convert a given character into uppercase.
Answer:
a) strlen();
b) strcat();
c) abs();
d) toupper();

Question 17.
What are the advantage of using broadband internet connection over a dial-up connection?
Answer:
The advantages are

• It is a high speed connection.
• It is always on connection.
• Simultaneous use of voice and data possible.

Question 18.
What is a computer worm? How does it differ from computer virus?
Answer:
It is a stand alone malware program that replicates itself in order to spread to other computers. It slows down the traffic by consuming the bandwidth. In 2000 a worm called “ILOVEYOU” is affected many computers.

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

Question 19.
The analytical Engine has many features found in modern digital computer. What are they?
Answer:
Analytical engine :- In 1833, Charles Babbage introduced this. Charles Babbage is considered as the “Father of computer” It is considered as the predecessor of today’s computer. This engine vyas controlled by programs stored in punched cards. These programs were written by Babbage’s assistant, Augusta Ada King, who was considered as the first programmer in the World.

Question 20.
NAND gate is called universal gate because all other logic gates can be derived using NAND gate alone. How will you connect NAND gates to implement inverter, OR gate and AND gate? Draw logic circuits.
Answer:
By using NAND and NOR gates only we can create other gate hence these gates are called Universal gate.

Question 21.
Write the statement of De Morgan’s First theorem. Prove it algebraically.
Answer:
(a + b))’ = a’.b’ OR The complement of the sum of boolean variables is equal to the product of their individual complements.
We have to prove that (a + b)’ = a’.b’
Let us take z = a + b (1)
z’ = (a + b)’ (2)
We know that by complementary law z + z’ = 1 and z.z’= 0
Replace z and z’ with the values of (1) and (2) respectively.
So (a + b) + (a + b)’ = 1 (3)
(a + b).(a + b)’= 0 (4)
Let us assume that De Morgan’s first theorem is true, so (a + b)’=a’.b’
Hence Equation (3) and (4) becomes as follows (a + b) + (a’, b’) =1 (5)
(a + b).(a’.b’) = 0 (6)
Now we have to prove Equations (5) and (6). If they are true then we will conclude that the De Morgan’s theorem is also true.
Consider the LHS of Eq. (5)
(a + b) + (a’.b’) = (a + b + a’). (a + b + b’) by Distributive law
= (a + a’ + b).(a + b + b’) by Commutative law.
= (1 + b).(a + 1) by Complementary law
= 1.1 (Basic Postulates)
= 1
= RHS
Now let us consider the LHS of Eq.(6).
(a + b).(a’.b’) = (a.a’.b’) + (b.a’.b’) Distributive law
= (a.a’.b’) + (b.b’.a’) Commutative law
= (0.b’) + (0.a’) Complementary law
= 0 + 0 (Basic postulates
= 0
= RHS
Hence the theorem is proved

Question 22.
Draw flow chart symbols and write their meanings standardized by American National Standards Institute.
Answer:
Flow chart symbols are explained below
1) Terminal (Oval)

It is used to indicate the beginning and ending of a problem

2) Input/Output (parallelogram)

It is used to take input or print output.

3) Processing (Rectangle)

It is used to represent processing
That means to represent arithmetic operation such
an addition, subtraction, multiplication….

4) Decision (Rhombus)

It is used to represent decision making. It has one entry flow and two exit flows but one exit path will be executed at a time.

5) Flow lines (Arrows)

It is used to represent the flow of operation

6) Connector

Question 23.
What is explicit type conversion (type casting)? Explain with example.
Answer:
This is done by the programmer. The programmer forcibly convert the data type into another type. Its syntax is (data type to be converted) expression;
Eg. int x=10;
(float) x;

Question 24.
What is an identifier? Write the rules to be followed while creating an identifier in C++.
Answer:
These are user defined words. Eg. Variable name, function name, class name, object name etc.
The rules are

1. It starts with alphabet.
2. Underscore is considered as an alphabet.
3. Digits can be used followed by an alphabet.
4. Keywords cannot be used.
5. Special characters cannot be used.

Question 25.
Write a list of operations that can be performed on arrays.
Answer:
Array operations – Traversal, Sorting and Searching.

Question 26.
Consider the following C++ statement:
char name [20];
cm >> name;
cout << name;
What will be the output if you input the string “Abdul Kalam”? Justify your answer. Rewrite the code using a console function to input a string.
Answer:
It is output is Abdul. Because cin reads the characters upto the space. Here space is the delimiter. To read characters including white spaces use gets() function. Instead of cin»name; use gets(name);

Question 27.
Write the two methods of calling functions in C++. What are the differences between these two methods?
Answer:
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.
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 28.
What is recursion? Write a recursive function that returns factorial of a non – negative integer. Rewrite the function without using recursion.
Answer:
A function calls itself is called recursive function. Using recursive function long int fac(int n)

{
if(n==0)
return(1);
else
retum(n*fac(n-1));
}
Without using recursive function long int fac(int n)
{
for(i=1;i<=n;i++)
fact=fact*i;
}

Question 29.
Write a brief description about any three wireless communication technologies using radio waves.
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.
3. Wi MAX(Wireless Microwave Access); It uses micro waves to transmit information across a network in a range 2 GHz to 11 GHz over very long distance.

Question 30.
Write any three advantages of social media.
Answer:

1. Bring people together: It allows people to maintain the friendship.
2. Plan and organize events: It allows users to plan and organize events.
3. Business promotion: It helps the firms to promote their sales.

Answer any two of the questions from 31 to 33. (2 × 5 = 10)

Question 31.
Write a description about general purpose application software.
Answer:
Programs developed to serve a particular application is known as application software, eg:- MS Office, Compression Utility, Tally etc.
Application software can further be sub divided into three categories.
a) Packages
b) Utilities
c) Customized Software

a) Packages: Application software that makes the computer useful for people to do every task. Packages are used to do general purpose application.

b) Utilities: Utilities are programs which are designed to assist computer for its smooth functioning.

c) Specific purpose software (Customized software): It is collection of programs which are developed to meet user needs to serve a particular application. It is also called tailor made software.

Question 32.
What is the use of looping statements? Looping / Explain elements of a looping statement with suitable example.
Answer:
Iteration statements: If we have to execute a block of statements more than once then iteration statements are used.

Question 33.
Explain advantaged of using networked computers instead of using stand -alone computers.
Answer:

• Resource sharing: All the computers in a network can share software (programs, data ………………..) and hardware (printer, scanner, CD drive etc.).
• 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.
• 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.
• Communication Medium: It is a powerful communication medium. We can exchange information between computers in a network.
• Scalable: This means, System performance can be increased by adding computers to a network.