Kerala Plus One Computer Science Question Paper SAY 2019 with Answers

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.