Plus One Computer Science Notes Chapter 1 The Discipline of Computing

Kerala Plus One Computer Science Notes Chapter 1 The Discipline of Computing

Summary
Computing milestones and machine evolution:
People used pebbles and stones for counting earlier days. They draw lines to record information. eg: 1 line for one, 2 lines for two, 3 lines for three, etc. In this number system the value will not change if the lines are interchanged. This type of number system is called non-positional number system.

Counting and the evolution of the positional number system:
In positional number system, each and every number has a weight. Earlier sticks are used to count items such as animals or objects. Around 3000 BC the Egyptians use number systems with radix 10(base-the number of symbols or digits used in the number system) and they write from right to left.

You can also read numpy where with examples.

Later Sumerian/Babylonian use number system with largest base 60 and were written from left to right. They use space for zero instead of a symbol, 0. In 2500 BC, the Chinese use simple and efficient number system with base 10 very close to number system used in nowadays.

In 500 BC, the Greek number system known as Ionian, it is a decimal number system and used no symbols for zero. The Roman numerals consists of 7 letters such as l, V, X, L, C, D, M. The Mayans used number system with base 20 because of the sum of the number of fingers and toes is 10 + 10 = 20.

It is called vigesimal positional number system. The numerals are made up of three symbols; zero (shell shape, with the plastron uppermost), one (a dot) and five (a bar or a horizontal line). To represent 1 they used one dot, two dots for 2, and so on
Plus One Computer Science Notes Chapter 1 The Discipline of Computing 1
The Hindu – Arabic number system had a symbol(0)for zero originated in India 1500 years ago. Consider the table to compare the number system

Roman NumeralsDecimal / Hindu – Arabic number
I1
V5
X10
L50
C100
D500
M1000

Evolution of the computing machine:
(a) Abacus:
In 3000 BC Mesopotamians introduced this and it means calculating board or frame. It is considered as the first computer for basic arithmetical calculations and consists of beads on movable rods divided into two parts. The Chinese improved the Abacus with seven beads on each wire. Different Abacus are given below.

Plus One Computer Science Notes Chapter 1 The Discipline of Computing 2

Plus One Computer Science Notes Chapter 1 The Discipline of Computing 3

(b) Napier’s bones:
A Mathematician John Napier introduced this in AD 1617.

(c) Pascaline:
A French mathematician Blaise Pascal developed this machine that can perform arithmetical operations.

(d) Leibniz’s calculator:
In 1673, a German mathematician and Philosopher Gottfried Wilhelm Von Leibniz introduced this calculating machine.

(e) Jacquard’s loom:
In 1801, Joseph Marie Jacquard invented a mechanical loom that simplifies the process of manufacturing textiles with complex pattern. A stored program in punched cards was used to control the machine with the help of human labour. This punched card concept was adopted by Charles Babbage to control his Analytical engine and later by Hollerith.

(f) Difference engine:
The intervention of human beings was eliminated by Charles Babbage in calculations by using Difference engine in 1822. It could perform arithmetic operations and print results automatically
Plus One Computer Science Notes Chapter 1 The Discipline of Computing 4

(g) 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 was 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.
Plus One Computer Science Notes Chapter 1 The Discipline of Computing 5

(h) Hollerith’s machine:
In 1887, Herman Hollerith an American made first electromechanical punched cards with instructions for input and output. The.card contained holes in a particular pattern with special meaning. The Us Census Bureau had large amount of data to tabulate, that will take nearly 10 years.

By this machine this work was completed in one year. In 1896, Hollerith started a company Tabulating Machine Corporation. Now it is called International Business Machines(IBM).

(i) Mark-1:
In 1944 Howard Aiken manufactured automatic electromechanical computer in collaboration with engineers at IBM that handled 23 decimal place numbers and can perform addition, subtraction, multiplication and subtraction.

Generations of computers:
There are five generations of computers from 16th century to till date.
Plus One Computer Science Notes Chapter 1 The Discipline of Computing 6

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
Plus One Computer Science Notes Chapter 1 The Discipline of Computing 7
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 follows the “Stored Program Concept”. Colossus is the secret code breaking computer developed by a British engineer Tommy Flowers in 1943 to decode German messages.

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.

A team contained John Bardeen, Walter Brattain and William Shockley developed this computer at Bell Laboratories. In this generation onwards the concept of programming language was developed and used magnetic core (primary) memory and magnetic disk(secondary) memory.

These computers used high level languages(high level language means English like statements are used)like FORTRAN (Formula translation) and COBOL(Common Business Oriented Language). The popular computers were IBM 1401 and 1620.

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. The high level language BASIC(Beginners All purpose Symbolic Instruction Code) was developed during this period.

The popular computers were IBM 360 and 370. Due to its simplicity and cheapness more people were used. The number of transistors on IC’s doubles approximately every two years. This law is called Moore’s Law, it is named after Gordon E Moore. It is an observation and not a physical or natural law.

Fourth generation computers (1971 onwards):
Microprocessors are used hence computers are called microcomputers. Microprocessor is a single chip which contains Large Scale of IC’s(LSI) like transistors, capacitors, resistors,etc due to this a CPU can place on a single chip. Later LSI were replaced by Very Large Scale Integrated Circuits(VLSI). The popular computers are IBM PC and Apple II.

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. The most common Al programming language are LISP and Prolog.

Evolution of computing:
Computing machines are used for processing or calculating data, storing and displaying information. In 1940’s computer were used only for single tasks like a calculator. But nowadays computer is capable of doing multiple tasks at a time.

The “Stored Program Concept” is the revolutionary innovation by John Von Neumann helped storing data and information in memory. A program is a collection of instructions for executing a specific job or task.

Augusta Ada Lowelace: She was the Countess of Lowelace and she was also a mathematician and writer. She is considered as the first lady computer programmer.

Programming languages:
The instructions to the computer are written in different languages. They are Low Level Language(Machine language), Assembly Language(Middle level language) and High Level Language(HLL).

In Machine Language 0’s and 1 ’s are used to write program. It is very difficult but this is the only language which is understood by the computer. In assembly language mnemonics (codes) are used to write programs
Plus One Computer Science Notes Chapter 1 The Discipline of Computing 8
Electronic Delay Storage Automatic Calculator(EDSAC) built during 1949 was the first to use assembly language. In HLL English like statements are used to write programs. A-0 programming language developed by Dr. Grace Hopper, in 1952, for UNIVAC-I is the first HLL.

A team lead by John Backus developed FORTRAN @IBM for IBM 704 computer and ‘Lisp’ developed by Tim Hart and Mike Levin at Massachusetts Institute of Technology. The other HLLs are C, C++, COBOL, PASCAL, VB, Java etc. HLL is very easy and can be easily understood by the human being.

Usually programmers prefer HLL to write programs because of its simplicity. But computer understands only machine language. So there is a translation needed. The program which perform this job are language processors.

Algorithm and computer programs:
The step-by-step procedure to solve a problem is known as algorithm. It comes from the name of a famous Arab mathematician Abu Jafer Mohammed Ibn Musaa Al-Khowarizmi, The last part of his name Al-Khowarizmi was corrected to algorithm.

Theory of computing:
It deals with how efficiently problems can be solved by algorithm and computation. The study of the effectiveness of computation is based upon a mathematical abstraction of computers is called a model of computation, the most commonly used model is Turing Machine named after the famous computer scientist Alan Turing.

1. Contribution of Alan Turing:
He was a British mathematician, logician, cryptographer and computer scientist. He introduced the concept of algorithm and computing with the help of his invention Turing Machine.

He asked the question Can machines think’ led the foundation for the studies related to the computing machinery and intelligence. Because of these contributions he is considered as the Father of Modern Computer Science as well as Artificial Intelligence.

2. Turing Machine:
In 1936 Alan Turing introduced a machine, called Turing Machine. A Turing machine is a hypothetical device that manipulates symbols on a strip of tape according to a table of rules. This tape acts like the memory in a computer. The tape contains cells which starts with blank and may contain 0 or 1.

So it is called a 3 Symbol Turing Machine. The machine can read and write, one cell at a time, using a tape head and move the tape left or right by one cell so that the machine can read and edit the symbol in the neighbouring cells. The action of a Turing machine is determined by

  1. the current state of the machine
  2. the symbol in the cell currently being scanned by the head and
  3. a table of transition rules, which acts as the program.

3. Turing Test:
The Turing test is a test of a machine’s ability to exhibit intelligent behaviour equivalent to, or indistinguishable from, that of a human. The test involves a human judge engages in natural language conversations with a human and a machine designed to generate performance indistinguishable from that of a human being.

All participants are separated from one another. If the judge cannot reliably tell the machine from the human, the machine is said to have passed the test. The test does not check the ability to give the correct answer to questions; it checks how closely the answer resembles typical human answers. Turing predicted that by 2000 computer would pass the test.

Plus One Computer Science Notes

Plus One Computer Application Improvement Question Paper Say 2018

Kerala Plus One Computer Application Improvement Question Paper Say 2018 with Answers

BoardSCERT
ClassPlus One
SubjectComputer Application
CategoryPlus One Previous Year Question Papers

Time Allowed: 2 hours
Cool off time: 15 Minutes
Maximum Marks: 60

General Instructions to Candidates:

  • There is a ‘cool off time’ of 15 minutes in addition to the writing time of 2 hours.
  • Use the ‘cool off time’ to get familiar with the questions and to plan your answers.
  • Read questions carefully before you answering.
  • Read the instructions carefully.
  • Calculations, figures, and graphs should be shown in the answer sheet itself.
  • Malayalam version of the questions is also provided.
  • Give equations wherever necessary.
  • Electronic devices except non-programmable calculators are not allowed in the Examination Hall.

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

Question 1.
Processed data is called ………….
Answer:
Information

Question 2.
Write the full form of HDMI.
Answer:
High Definition Multimedia Interface

Question 3.
The process of converting source code into object code is called …………..
Answer:
Translation or Compilation or Interpretation

Question 4.
C++ program execution starts and ends within …………. function.
Answer:
main()

Question 5.
Give an example for search engine.
Answer:
Google / Yahoo / Bing / Ask

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

Question 6.
Fill in the blanks.
a) (DA)16 = (…….)2
b) (25)10 = (…….)8
Answer:
a) D = 1101
A = 1010
(11011010)2
b) Divide the number 25 by 8 successively, and write down the reminders from bottom to top.
Hence the answer is (31)8

Question 7.
Name any four parts on the motherboard.
Answer:
Ports are PS/2, Serial, Parallel, HDMI, VGA, USB, Audio, LAN port, etc.

Question 8.
Compare RAM and ROM.
Answer:

RAMROM
1. Random Access Memory1. Read-Only Memory
2. Volatile2. Non-Volatile
3. Faster3. Slower
4. Read and Write Memory4. Read-only
5. Stores programs and data for CPU5. Stores boot-up program

Question 9.
Write short notes on the following:
a) Coding
b) Debugging
Answer:
a) Coding – The process of writing programs to solve a problem is called coding
b) Debugging – It is the process of detecting and correcting errors in a program

Question 10.
Briefly explain any two expressions in C++.
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 11.
Rewrite the following C++ statement using if ……….. else statement.
cout<<result=mark>30?
“Passed” : “Failed”;
Answer:
if(mark>30)
cout<<“Passed”;
else
cout<<“Failed”;

Question 12.
List the four important elements of a loop.
Answer:
Following are the components of loop statement

  1. Initialization – The loop variable must be initialized
  2. Checking – Loop variable must be checked.
  3. Body – The statements to be executed is written in the body
  4. Update – The loop variable must be updated

Question 13.
Explain any two advantages of computer networks.
Answer:
The advantages of Networks are given below.

  • 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 mainframe computer can be 10 times faster than a PC but it costs thousand times a PC. Therefore instead of a mainframe 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.

Question 14.
Differentiate between HUB and SWITCH.
Answer:
Hub: It is a small, simple and inexpensive device used to connect computers(devices) to a network. If a computer wants to transmit data to another computer. First it sends to the hub, the hub retransmits this data to all other computers. Each and every computer gets the data and check whether it is for them or not. It increases the network traffic and hence the transmission speed is low.

Switch: It is an expensive device used to connect computers(devices) to a network. Unlike hub, switch transmit data not to all computers, it retransmits data only to the intended computer. So the traffic is less and speed is high
We can summarise it as follows

HubSwitch
1. Cheap1. Expensive
2. Not an intelligent device2. Intelligent device
3. High traffic3. Less traffic
4. Low speed4. High speed

Question 15.
List the hardware and software requirments for connecting computer to internet.
Answer:
The hardware and software requirement for internet.

  • A computer with a modem (internal/external)
  • A telephone connection
  • An account with an ISP
  • A browser S/W eg: Internet Explorer or Mozilla…

Question 16.
Briefly describe any two benefits of e-Governance.
Answer:
Benefits of E-governance: Its main aim is to provide better service to the people at any time and place with high speed. In the modern world it is very helpful and convenient to the people.

  • It enables automation of Govt, services
  • It ensures the participation of citizens hence strengthen the democracy
  • It ensures more transparency hence eliminates corruption
  • It enhances responsibilities of various Govt. Departments
  • Its proper implementation saves time and money of the people by avoiding unnecessary visits to offices.

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

Question 17.
Represent -35 in the following forms.
(Hint: Use 8 bit form of representation).
a) Sign and magnitude.
b) One’s complement.
c) Two’s complement.
Answer:
a) In SMR, MSB is 1 for negative numbers -35 = 10100011
b) One’s complement – First find the binary equivalent of the positive number and change all ones to zero and all zeroes to one
+35 = 00100011
One’s complement of -35 is 11011100
c) Two’s complement – Add 1 to one’s complement form Two’s complement of -35 is 11011100 + 1 = 11011101

Question 18.
Draw a flowchart to find the sum and average of three given numbers.
Answer:
Plus One Computer Application Improvement Question Paper Say 2018, 1

Question 19.
Explain two types of documentations in programming.
Answer:
Documentation: We can write comments in the source code as part of documentation that helps to modify the program in future. It is known as internal documentation.
External Documentation: This includes preparation of system manual and user manual containing the functioning of the system, its requirements, installation etc.

Question 20.
Define tokens in C++. List any four types of tokens.
Answer:
Token: It is the smallest individual units similar to a word in English or Malayalam language. C++ has 5 tokens
Keywords, Identifier, Literals (Constants), Punctuators and Operators.

Question 21.
Consider X = 5 and Y = 2 and write the output of the following expressions.
a) X== y&&Y > X
b) X>=2 || Y==2
c) (X*X) – y
Answer:
a) 5==2&&2>5
False && False
Answer is False( or 0)
b) 5>=2 || 2 == 2
True || True
Answer is True
c) (5*5)-2
25-2
The answer is 23

Question 22.
Explain any three types of statements in C++.
Answer:
Statements are smallest executable units end with semicolon.
Eg: Declaration
int x;
assignment
x=5;
input
cin>>x;
output
cout<<x;
and control statements

Question 23.
Explain implicit and explicit type conversion with suitable examples.
Answer:
Type conversion: Type conversions are of two types.
1) Implicit type conversion: This is performed by C++ compiler internally. C++ converts all the lower sized- data type to the highest sized operand. It is known as type promotion. Data types are arranged lower size to higher size is as follows.

unsigned int(2 bytes), int(4 bytes),long (4 bytes), unsigned long (4 bytes), float(4 bytes), double (8 bytes), long double(10 bytes)

2) Explicit type conversion: It is known as typecasting. This is done by the programmer. The syntax is given below.
(data type to be converted) expression
Eg. int x = 10;
(float) x; This expression converts the data type of the variable from integer to float.

Question 24.
Write a C++ program to input a digit and print it in words.
(Hint: If digit = 1 then print. “ONE”)
Answer:
#include<iostream>
using namespace std;
int main()
{
int n;
cout<<“Enter a number”;
cin>>n;
switch(n)
{
case 1:
cout<<‘‘One”;
break;
case 2:
cout<<“Two”;
break;
case 3:
cout<<“Three”;
break;
case 4:
cout<<“Four”;
break;
case 5:
cout<<“Five”;
break;
case 6: cout<<“Six”;
break;
case 7:
cout<<“Seven”;
break;
case 8:
cout<<“Eight”;
break;
case 9:
cout<<“Nine”;
break;
case 0:
cout<<“Zero”;
break;
default:
cout<<“lnvalid digit”;
}
}

Question 25.
Compare while loop and do while loop in C++.
Answer:

While loopDo while loop
1. Entry controlled2. Exit controlled
1. If the condition is false in the beginning the body will not execute2. Even though the condition is false in the beginning, the body of the loop will be executed once

Question 26.
What is web browsing? Write the names of four web browsers.
Answer:
The process of accessing internet is called web browsing. The popular web browsers are Google chrome, Microsoft Internet Explorer, Mozilla Firefox, etc.

Question 27.
Explain any three e-Businees services.
Answer:
E business(electronic Business): Providing services or running business through internet is called E-business.

  1. e-commerce and e-business: Both are different. E-commerce means Electronic commerce. It includes exchange of goods or services through internet that involves exchange of money whereas e-Business includes activities to run a business.
  2. Electronic Payment System(EPS): It is also called plastic money that is electronically exchange money between two individuals or firms(buyers and sellers) in an online environment.
  3. E-banking (Electronic Banking): Through electronic channel doing all the banking activities at any time and place through internet.

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

Question 28.
a) “e-Waste is one of the major problems which
we are facing all over the world.” Justify the statement. (1)
b) Explain e-Waste disposal methods. (2)
c) Define the term, green-computing. How can you implement green-computing? (2)
Answer:
a) Yes, This is one of the major problems which we are facing all over the world
b) e-Waste disposal methods
1) Reuse: Reusability has an important role of e-Waste management and can reduce the volume of e-Waste
2) Incineration: It is the process of burning e-Waste at high temperature in a chimney
3) Recycling of e-Waste: It is the process of making new products from this e-Waste.
4) Landfilling: It is used to level pits and cover by thick layer of soil.
5) Following are the steps to promote green computing

  • Green design: Design energy efficient and eco-friendly devices
  • Green manufacturing: reduce non-eco-friendly parts while manufacturing
  • Green use: Use energy saver devices
  • Green disposal: Use easily disposable devices

Question 29.
a) Consider the structure of C++ program given below and answer the following question.
#include<iostream>
using namespace std;
int main ()
{
statements;
}
Which is the preprocessor directive statement in the code? (1)
b) Explain the use header files in a program. (2)
c) Write C++ program to print the following message.
(Hint: Use only one cout statement).
“SMOKING IS INJURIOUS TO HEALTH”
“SAY GOODBYE TO DRUGS” (2)
Answer:
a) #include
b) Header files help us to include the associate files that needed in our program.
c) #include<iostream>
using namespace std;
int main()
{
cout<<“\”SMOKING IS INJURIOUS TO HEALTH\”
\n \”SAY GOODBYE TO DRUGS\””;
}

Question 30.
“Computer network has an important role in the modern communication”.
a) What is data communication? (1)
b) Explain any two guided media. (2)
c) List any four data communication devices. (2)
Answer:
a) Data communication is the exchange of information between computers

b) Guided Media

  • Twisted Pair cable – 2 types unshielded twisted pair and shielded twisted pair. Two copper wires individually insulated and twisted around each other and put in a plastic cover.
  • Coaxial cable – A sturdy copper wire is insulated by plastic, it is covered just like a mesh by a conductor which is enclosed in an protective plastic coating, it is expenssive, less, flexible and more difficult to install. But it is more reliable and carry for higher data rates.
  • Optical fibre – These are made of glass fibres that are enclosed in a plastic jacket. It uses light instead of electrical signals. The light sources are LED or ILD.

C) NC, HUB, Switch, Repeater, Bridge, Router, Gateway

Plus One Computer Application Previous Year Question Papers and Answers

Plus One Computer Application Previous Year Question Paper March 2019

Kerala Plus One Computer Application Previous Year Question Paper March 2019 with Answers

BoardSCERT
ClassPlus One
SubjectComputer Application
CategoryPlus One Previous Year Question Papers

Time Allowed: 2 hours
Cool off time: 15 Minutes
Maximum Marks: 60

General Instructions to Candidates:

  • There is a ‘cool off time’ of 15 minutes in addition to the writing time of 2 hours.
  • Use the ‘cool off time’ to get familiar with the questions and to plan your answers.
  • Read questions carefully before you answering.
  • Read the instructions carefully.
  • Calculations, figures, and graphs should be shown in the answer sheet itself.
  • Malayalam version of the questions is also provided.
  • Give equations wherever necessary.
  • Electronic devices except non-programmable calculators are not allowed in the Examination Hall.

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

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

Question 2.
Pictorial representation of an algorithm is known as …………..
Answer:
Flowchart

Question 3.
What is the escape sequence characterfor new line in C++ program?
Answer:
\n

Question 4.
The starting symbol of a preprocessor directive statement is ………….
Answer:
#

Question 5.
Write the full form of MAC.
Answer:
Media Access Control

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

Question 6.
What is the importance of registers in computer system? Name any two registers.
Answer:
Registers are temporary storage locations inside the CPU. It stores the intermediate results temporarily. Memory Address Register, Instruction Register, Memory Buffer Register, Program Counter, Accumulator (Any 2)

Question 7.
What do you mean human ware? Give any two examples.
Answer:
Persons (Humans) who use computers are called human ware. System Administrator, System Manager, System Analyst, DBA, Programmers and Naive Users.

Question 8.
Explain any two limitations of flow chart.
Answer:
The limitations are given below

  1. To draw a flowchart, it is time consuming and laborious work.
  2. If any change or modification in the logic we may have to redraw a new flow chart.
  3. No standards to determine how much detail can include in a flowchart.

Question 9.
Differentiate between character literal and string literal.
Answer:
Character literal: A single character enclosed in single quotes. Eg. ‘M’, ‘F’, etc
String literal: A combination of characters enclosed in double quotes. Eg. “India”

Question 10.
What is the use of comments in a programme? List out two ways to Include comments in C++ program.
Answer:
To give tips in between the program comments are used. A comment is not considered as the part of program and cannot be executed. There are 2 types of comments single line and multiline.
Single line comment starts with //(2 slashes) but multi line comment starts with /* and ends with */

Question 11.
List out type modifiers 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.
Assume that recently your school computer lab is networked. List any four advantages you can experienced when using networked computers instead of stand alone computers.
Answer:
The advantages of Networks are given below.

  • 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.

Question 13.
Name the major parts of an optical fibre cable.
Answer:
Optical fibre has the following parts

  • Core: The thin glass rods that carries the light signals
  • Cladding: The outer optical material surrounding the core.
  • Coating: The plastic coating that act as a shield.
  • Jacket: Outer covering of the cable.

Question 14.
“Servers have much importance in a client server network”. Write the importance and list any two classifications of servers.
Answer:
A server is a powerful computer with high storage capacity that provides services like sharing data, software and hardware.
Eg. File server, Print Server, Database server, Web server Etc.

Question 15.
E-mail is a popular communication tool. Discuss any two advantages of E-mail.
Answer:
The advantages of E-mail is speed, easy to use, facility for attach files, eco-friendly, cost-effective, anywhere any time, etc.

Question 16.
Write any two challenges for implementing e-Governance.
Answer:
Challenges to E-Governance:

  • Due to lack of e-Literacy, there is a difficulty to access the service of E-Governance.
  • High security measures are required because of possibility of cyber attack.
  • Implementation and maintenance requires huge amount and planning
  • Some people refuses to give personal information due to anxiety
  • Various Departments’ integration is needed for the efficiency and effectiveness of e-Governance

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

Question 17.
Explain any three freedom designed by FSF for software.
Answer:
The Four freedoms are

  1. Freedom 0: To run program for any purpose
  2. Freedom 1: To study how it works and allows you to adapt according to your needs. Also allows to access source code.
  3. Freedom 2: Allowsto take copies and distribute
  4. Freedom 3: Allows you t6 change source code and release the program.

Question 18.
As a student, explain any three approaches that you can adopt to Promote ‘Green Computing’.
Answer:
Following are the steps to promote green computing

  • Green design: Design energy efficient and eco-friendly devices
  • Green manufacturing: reduce non eco-friendly parts while manufacturing
  • Green use: Use energy saver devices
  • Green disposal: Use easily disposable devices

Question 19.
Differentiate between Entry Controlled Loop and Exit Controlled loop.
Answer:
An entry controlled loop first checks the condition and execute(or enters into) 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 20.
Write an algorithm to find the biggest of two numbers.
Answer:
Step 1: Start
Step 2: Input 2 numbers. n1, n2
Step 3: If n1>n2 then
Step 4: Print n1
Step 5: Else
Step 6: Print n2
Step 7: Stop

Question 21.
What is statements? Explain any two types of statements in C++.
Answer:
Statements are smallest executable units end with semicolon.
Eg: Declaration
int x;
assignment
x=5;
input
cin>>x;
output
cout>>x;
and control statements

Question 22.
a) What is constant?
b) Write the keyword for constant declaration in C++.
c) Give an example.
Answer:
a) Its value doesn’t change during execution.
b) const
c) const int bp=100; (Note that value must be initialized)

Question 23.
Explain the different types of logical operators.
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(0).
If x=1 and y=0 then
Plus One Computer Application Previous Year Question Paper March 2019, 1
Both operands must be true to get a true value in the case of AND (&&) operation
If x = 1 and y = 0 then
Plus One Computer Application Previous Year Question Paper March 2019, 2
Either one of the operands must be true to get a true value in the case of OR (||) operation
If x = 1 and y = 0then
Plus One Computer Application Previous Year Question Paper March 2019, 3

Question 24.
Consider the following code.
int i=1
for(;;)
{
cout<<i<<“\n”
}
a) Find the output
b) Rewrite the code by using while loop with i<=10 and i = i+2 inappropriate place for successful code execution.
Answer:
a) It is an infinite loop. It prints 1 infinitely
b) int i=1;
while(i<=10)
{
cout<<i<<“\n”;
i = i+2;
}

Question 25.
a) Define Network Topology.
b) Compare Ring Topology with Star Topology.
Answer:
The way in which the nodes are physically interconnected to form a network is called a topology.

Star topology:

  • It looks like a star
  • All computers are connected to a hub or switch
  • The signal is sent only to the intended node
  • Failure of hub/switch leads to failure of network

Ring topology:

  • It looks like a ring
  • There is no central computer
  • The signal transmitted to each node
  • If one node fails, entire network will fail

Question 26.
Your, friend wants to take an internet connection. Explain and compare any three types of broadband connectivity available now-a-days.
Answer:
Wireless broadband connectivity
a) Mobile broadband: Accessing Internet using wireless devices like mobile phones, tablet, USB dongles.
b) 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.
c) Satellite broadband: Accessing internet through satellite. A Very Small Aperture Terminal(VSAT) dish antenna and transceiver and modem are required at the user’s location. Expensive and highspeed.

Question 27.
e-Learning playing an important role in education field.
Discuss any three advantages of e-Learning.
Answer:
Advantages of E Learning:

  • It can offer variety courses to large number of students from distant location.
  • It saves journey time and money, instructor fees, etc.
  • People can enjoy e Learning with lower cost
  • It enables people to do courses conducted by national or international institutions.

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

Question 28.
a) List down the functional units of a computer by using a diagram. (2)
b) What are the advantages and limitations of a computer? (3)
Answer:
a) 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.
Plus One Computer Application Previous Year Question Paper March 2019, 4

b)
Advantages of computer:

  • Speed: It can perform operations at a high speed.
  • Accuracy: It produces result at a high degree of accuracy.
  • Diligence: Unlike human beings, a computer is free from monotony, tiredness, lack of concentration etc. We know that it is an electronic machine. Hence it can work hours without making any errors.
  • Versatility: It is capable of performing many tasks. It is useful in many fields.
  • Power of Remembering: A computer consists of huge amount of memory. So it can store and recall any amount of information without delay.

Disadvantages of computer:

  • No IQ: It has no intelligent quotient. Hence they are slaves and human beings are the masters. It can’t take its own decisions.
  • No feelings: Since they are machines they have no feelings and instincts.

Question 29.
a) What is operator? Classify the operators based on number of operands. (2)
b) Find the output of the following operations if x = -11 and Y = 3
i) -x + -y
ii) x% – y
iii) x% – 11
iv) (x>y)&&(x<y)
v) ! (x<y)
vi) x * y (3)
Answer:
a) An operator is a symbol used to perform an operation. The classifications are

  • Unary: It requires only one operand
  • Binary: It requires two operands
  • Ternary: It requires three operands

b) i) -(-11)+ -3 = 8
ii) -11 % -3 = -2
Hi) -11 % -11 = 0
iv) (-11>3)&&(-11<3)
0&&1 = 0(false)
v) !(-11<3) = !(1) = 0(false)
vi) -11*3 = -33

Question 30.
a) List the four components of a Loop Statements.
b) Write a C++ program to find the sum of numbers up to 100 by using any loop statement.
Answer:
a) Following are the components of loop statement

  • Initialization: The loop variable must be initialized
  • Checking: Loop variable must be checked.
  • Body: The statements to be executed is written in the body
  • Update: The loop variable must be updated

b) #inclUde<iostream>
using namespace std;
int main()
{
int i=1, sum=0;
for(i=1;i<=100;i++)
sum+=i;
cout<<“The sum of numbers upto 100 is “<<sum;
}

Plus One Computer Application Previous Year Question Papers and Answers

Plus One Computer Science Improvement Question Paper Say 2018

Kerala Plus One Computer Science Improvement Question Paper Say 2018 with Answers

BoardSCERT
ClassPlus One
SubjectComputer Science
CategoryPlus One Previous Year Question Papers

Time Allowed: 2 hours
Cool off time: 15 Minutes
Maximum Marks: 60

General Instructions to Candidates:

  • There is a ‘cool off time’ of 15 minutes in addition to the writing time of 2 hours.
  • Use the ‘cool off time’ to get familiar with the questions and to plan your answers.
  • Read questions carefully before you answering.
  • Read the instructions carefully.
  • Calculations, figures, and graphs should be shown in the answer sheet itself.
  • Malayalam version of the questions is also provided.
  • Give equations wherever necessary.
  • Electronic devices except non-programmable calculators are not allowed in the Examination Hall.

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

Question 1.
Name the keyword that indicates an empty set of data.
Answer:
void

Question 2.
……… built-in function is used to terminate the program.
Answer:
exit(0)

Question 3.
Name the ancient number system with the largest base.
Answer:
Sumerian / Babylonian number system

Question 4.
In ………… network topology, each node is directly connected to a hub/switch.
Answer:
star topology

Question 5.
Name the character function used to accept a string including whitespace.
Answer:
gets() o rgetline()

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

Question 6.
What are the characteristics of fourth generation computers?
Answer:
Characteristics are given below

  • Micro processors are used
  • The size of the computer is reduced much
  • Speed increases
  • Cost decreases
  • More used friendly

Question 7.
Draw the truth table of NAND gate.
Answer:
Truth table of NAND gate is given below
Plus One Computer Science Improvement Question Paper Say 2018, 1

Question 8.
What are the major functions of operating system?
Answer:
Process management, Memory handling, Device management and file management.

Question 9.
Write an algorithm to find the sum and average of three numbers.
Answer:
Step 1 : Start
Step 2 : Read 3 numbers n1, n2 and n3
Step 3 : sum=n1+n2+n3
Step 4 : avg=sum/3
Step 5 : Print Sum,Avg
Step 6 : Stop

Question 10.
What is meant by tokens? Name the 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.
Keywords, Identifier, Literals (Constants), Punctuators and Operators.

Question 11.
What is the use of the keyword “Const”? Give an example.
Answer:
The keyword const is used to declare constants in a program. Its value doesn’t change during execution. Eg. const float pi = 3.1415

Question 12.
Illustrate the memory allocation for a single dimensional array in C++.
Answer:
Plus One Computer Science Improvement Question Paper Say 2018, 2

Question 13.
Consider the following statements.
Char name [20];
Cin>>name;
Cout<<name;
What will be the output if you input the string “GREEN COMPUTING”? Justify your answer.
Answer:
The output is GREEN. This is because of cin statement that will take upto the space. Here space is the delimiter. To resolve this gets() function can be used. To use gets() and puts() function the header file cstdio must be included.

Question 14.
Correct the program and write the output.
#include<iostream>
using namespace std;
int main ()
{
int n = 25;
float b = sqrt (n);
cout<<b;
return 0;
}
Answer:
use mathematical built in function the header file cmath must be included.
#include<cmath>
The output is square root of 25 is 5

Question 15.
Write a short note on WiMAX.
Answer:
Wi MAX (Wireless Microwave Access): It uses microwaves to transmit information across a network in a range 2 GHz to 11 GHz over very long distance.

Question 16.
Name any four Mobile Operating Systems.
Answer:
Popular Mobile OSs are Android from Google, iOS from Apple, BlackBerry OS from BlackBerry and Windows Phone from Microsoft.

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

Question 17.
Fill in the blanks.
a) (……….)10 = (11001)2
b) (0.625)10 = (………)2
c) (AB)16 = (……….)2
Answer:
a) 25
b) (0.101)2
c) (10101011)2

Question 18.
a) MIDI stands for (1)
b) Draw the logical circuit for the Boolean expression. \(\overline{\mathrm{A}}\).B+A \(\overline{\mathrm{B}}\) (2)
Answer:
a) Musical Instrument Digital Interface
b)
Plus One Computer Science Improvement Question Paper Say 2018, 3

Question 19.
a) The fastest memory in a computer is …………
b) Categorize the software given below into operating system, application package and utility program. Linux, Open Office Calc, Windows, WinZip, Kaspersky, OpenOffice Writer
Answer:
a) Register
b) OS – Linux, Windows
Application – Open Office calc, Open Office writer
Utility Programs – Winzip, Kaspersky

Question 20.
a) Program written in HLL is known as …………
b) What is the need of documentation for a program?
Answer:
a) Source Code

b) There are 2 types of documentation they are internal and external documentation.
Internal Documentation: We can write comments in the source code as part of documentation that helps to modify the program in future. It is known as internal documentation.

External Documentation: This includes preparation of system manual and user manual containing the functioning of the system, its requirements, installation, etc.

Question 21.
a) What is an algorithm?
b) Distinguish between logical error and syntax error in a program.
Answer:
a) Step by step procedure to solve a problem is called algorithm.

b) In general there are two types of errors syntax errors and logical errors. When the rules or syntax of the language are not followed then syntax errors occurred and it is displayed after compilation. .When the logic of a program is wrong then logical errors occurred and it is not displayed after compilation but it is displayed in the execution and testing phase.

Question 22.
a) Arrange the fundamental data types in ascending order of their memory requirement. (1)
b) What is the use of size of operator in C++? Give an example. (2)
Answer:
a) char, int/float, double
b) size of( ): This operator is used to find the size used by each data type.
Eg. size of(int)gives 4

Question 23.
Explain the looping statements in C++.
Answer:
Iteration statements: If we have to execute a block of statements more than once then iteration statements are used.

1) while statement
It is an entry controlled loop. An entry controlled loop first checks the condition and execute(or enters into) 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 checkthe 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 wiil be continue.

Question 24.
An array AR contains the elements 15, 81, 63, 25, 45, 58, 90. Illustrate the working of binary search technique to locate the element 45.
Answer:
Binary search can be performed only on sorted arrays. So the given array AR to be sorted by using bubble sort or selection sort. So the sorted array is as follows.
15, 25, 45, 58, 63, 81, 90
Step I: First we check the element with the middle element.
Here I = 0 and u = 6
m = (I + u)/2 = 3
Here the element AR[3] is 58,
It is greater than the element to be searched i.e. 45
So the upper bound is m – 1
i.e. u = 3 – 1 = 2
Step 2: again find m.
m = (I + u)/2 = (0 + 2)/2 – 1
Here the element AR[1] is 25.
It is less than the element to be searched i.e. 45
So the lower bound is m + 1
i.e. I = 1 + 1 = 2
Step 3: Again find m
m = (I + u)/2 = (2 + 2)/2 = 2
Here the element AR[2] is 45
The element is found and hence the search is finished.

Question 25.
Illustrate the working of bubble sort method for sorting the elements 23, 52, 43, 61, 73 and 28 in ascending order.
Answer:
Bubble sort
Consider the first 2 elements of the numbers and compare it.
23 is less than 52. So no need to interchange both of them. Then the numbers are 23, 52, 43, 61, 73, 28.
Next compare 52 and 43. Here 52 is greater.
So interchange both of them. Then the numbers are 23,43,52,61,73,28.
Next compare 52 and 61. Here 52 is leaser.
So no need to interchange.
Next compare 61 and 73. Here also no need to interchange.
Next compare 73 and 28. Here 73 is greater.
So interchange both of them. After the first phase the largest number is on the right side.
The numbers are as follows 23, 43, 52, 61, 28, 73.
Similarly do the remaining numbers except 73.
At last we will get the result as follows
23,28,43,52,61,73.

Question 26.
Distinguish between exit ( ) function and return statement.
Answer:
Both are used to terminate the program but both are different. Return is a keyword and exit(0) is a function.The difference is, we can use more than one exit(0) function but we can use only one return statement in a scope. To use exit(0), the header file cstdlib should be used.

Question 27.
a) Write the name of any two header files used in C++programs.
b) Write the role of header files in C++ programs.
Answer:
a) iostream, cstdio, cmath, cstring, etc
b) Header files help us to include the associate files that needed in our program.

Answer any 2 questions from 28 to 30. Each carries5 scores. (2 × 5 = 10)

Question 28.
a) 1 Byte = …….. Bits.
b) Explain the various types of memories in a computer system.
Answer:
a) 8 bits

b) Memory:
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 information(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,(It is permanent). In ROM a “boot up” program called BIOS (Basic Input Output System) is stored to “boots up” the computer when it switched on. Some ROMs are given below.

  • PROM
  • EPROM
  • EEPROM

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.
i) Magnetic storage device: It uses plastic tape or metal/plastic discs coated with magnetic material.

  • Hard Disk

ii) Optical storage device.
Optical Disk: The high power laser uses a concentrated, narrow beam of light, which is focuses and directed with lenses, prisms and mirrors for recording data. This beams burns very very small spots in master disk, which is used for making molds and these molds are used for making copies on plastic disks. A thin layer of aluminium followed by a transparent plastic layer is deposited on it. The holes made by the laser beam are called pits, interpreted as bit 0 and unburned areas are called lands interpreted as bit 1. Lower power laser beam is used to retrieve the data.

  • DVD (Digital Versatile Dipc)
  • Blu-ray Disc

iii) Semiconductor storage (Flash memory):
It uses EEPROM chips. It is faster and long lasting.

  • USB flash drive: It is also called thumb drive or pen drive. Its capacity varies from 2 GB to 32 GB.
  • Flash memory cards: It is used in Camera, Mobile phones, tablets etc to store all types of data.

Question 29.
Write a program to check whether the given number is prime or not.
Answer:
#include<iostream>
using namespace std;
intmain()
{
int n,i;
cout<<“Enter a number”;
cin>>n;
for(i=2;i<=n/2;i++)
{
if(n%i==0)
{ cout<<n<<“ is not a prime no.”;
return 0;
}
cout<<n<<“ is a prime”;
}

Question 30.
a) What is peer-to-peer network?
b) Specify the type of network given below.
ATM network, Cable television network, Network within the school. Network at home using bluetooth, Telephone network, Railway network.
Answer:
a) Peer to peer: in this configuration all the computers have equal priority. That means each computer can function as both a client and a server. There is no dedicated server.

b) PAN – network at home using Bluetooth
LAN – network within the school
MAN – Cable TV network
WAN – Railway, Telephone, Internet, ATM

Plus One Computer Science Previous Year Question Papers and Answers

Plus One Computer Science Previous Year Question Paper March 2019

Kerala Plus One Computer Science Previous Year Question Paper March 2019 with Answers

BoardSCERT
ClassPlus One
SubjectComputer Science
CategoryPlus One Previous Year Question Papers

Time Allowed: 2 hours
Cool off time: 15 Minutes
Maximum Marks: 60

General Instructions to Candidates:

  • There is a ‘cool off time’ of 15 minutes in addition to the writing time of 2 hours.
  • Use the ‘cool off time’ to get familiar with the questions and to plan your answers.
  • Read questions carefully before you answering.
  • Read the instructions carefully.
  • Calculations, figures, and graphs should be shown in the answer sheet itself.
  • Malayalam version of the questions is also provided.
  • Give equations wherever necessary.
  • Electronic devices except non-programmable calculators are not allowed in the Examination Hall.

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:

  1. Reuse: Reusability has an important role of e-Waste management and can reduce the volume of e-Waste.
  2. Incineration: It is the process of burning e-Waste at high temperature in a chimney
  3. Recycling of e-Waste: It is the process of making new products from this e-Waste.
  4. 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 into) 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 names 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 data type 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:

LinearBinary
1. No need of sorted array1. Need of sorted array
2. Searching is slower for larger array.2. It is faster
3. It starts checking from the first element and checks all elements.3. 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 16th 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 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). Alis 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:
Plus One Computer Science Previous Year Question Paper March 2019, 1

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 → 1B
(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

  • Arithmetic – It consists of arithmetic operators and operands eg. a+5, b%10, etc
  • Relational – It consists of relational operators and operands eg. a>5, b==5, etc
  • 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. pout.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 programming.
Answer:
Merits of modular programming is

  • It reduces the size of the program
  • Less chance of error
  • It reduces programming complexity
  • 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 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 outgoing network traffic by analyzing the data and then provides security to the computer network in an organization from other networks (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.
b) Rearrange the following memories in descending order depending on their speed.
(Hard disk, RAM, Cache Memory, Registers)
c) List four major functions of operating system.
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.
b) Read the following C++ statement and rewrite using if……. else.
(a>b)? cout<<a:
cout<<b;
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<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.
Eg.
#include<iostream>
using namespace std;
main()
{
int i=1;
while(i<10)
{
cout<<i<<endl;
if(i==5)
break;
i++;
}
}

3) continue statement:- It bypasses one iteration of the loop.
Eg.
#include<iostream>
using namespace std;
main()
{
int i=0;
while(i<10)
{
i++;
if(i==5) continue;
cout<<i<<endl;
}
}
b) if(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 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 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.

Plus One Computer Science Previous Year Question Papers and Answers