Computer Studies (general group) Solved Past Paper 10th Class 2013 Karachi Board

Section “A” Multiple choice Question (M.C.Qs)

(i) The device through which we enter the data into the computer is known as:
(a) input Davies
(b) Output Device
(c) I/O Device
(d) All of these

(ii) The physical structure of the computer is called:
(a) Hardware.
(b) Software
(c) Firmware
(d) Machine ware

(iii) High level language are nearest to the:
(a) Machine Language
(b) Hunum Language
(c) Assembly Language
(d) None of these

(iv) This command clears the Monitor screen:
(a) CLR
(c) CLS

(v) A Dot Matrix Printer is a/an:
(a) Input device
(b) Impact printer
(c) Non-impact printer
(d) None of these

(vi) The command used to create a sub directory:

(vii) Read statement Is a pair of:
(a) FOR
(e) DATA

(viii) Pictorial Diagram of program is called:
(a) Logical Flaw Chart
(b) System Flow Chart
(e) Psedo Code
(d) Coding

(ix) A process of error removing is called:
(a) Testing
(b) Defining
(c) Debuuing
(d) Coding

(x) The base of Binary number ill:
(a) 2
(b) 10
(c) 8
(d) 16

(xi) A looping a loop is called:
(a) Post test Loop
(b) Pre-test Loop
(c) Nested Loop
(d) . Condition Loop .

(xii) The statement which print. data on paper is:
(a) LUST

(xiii) The data consists of whole number:
(a) Numeric
(b) Integer
(c) Real
(d) None of these

(xiv) A set of instructions is called:
(a) Program
(b) Instruction
(c) Data
(d) Information

(xv) The abbreviation of American Standard Code for Information Interchange ls:
(a) ASCU
(c) ANSI
(d) ASC112

Section “B” Short Question Answer

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(3) It still required frequent maintenance.

Third Generation Computer (1965 – 1970)

this generation the Integrated Circuits (IC) were used. An Integrated circuits contains many electronic components on a single clip. The disk oriented systems were made at the end of this generation. The size of computer became very small with better performance and reliability. High level programming languages were extensively used. In 1969 the first poprocessor chip INTEL 4004 was developed but it W4S used only in calculation.

Advanuge: of Third Generation

(1) Smaller in size as compared to second generation.
(2) More reliable.
(3) Less electricity consumption.

Disadvanuges of Third Generation

(1) Air conditioning was required in many cases due to ICs.
(2) Very advance technology was required to make the ICs

Fourth Generation (1971 – 1981)

The Integrated Circuit were more developed and called small scale integration (551) after sometime the 551 were more developed and termed as large scale integration (LSI). There was a great versatility of Input/Output devices. The first microprocessor which is used in personal computers (PS) was INTEl: 8080. The snitch floppy disk was also introduced in 1971. While hard disk  was introduced in 1973. The 5.25 inch of floppy disk was first time used in 1978. The optical disk was developed in 1980. First portable computer “Osborne I” was marketei in 1981 

Advantages of Fourth Generation

(1) Smaller in size and much reliable.
(2) No cooling system is required in many cases.
(3) Totally general purpose computers

Disadvantages of Fourth Generation

Very advanced technology was required to fabricate to the ICs

Fifth Generation (1981 – onwards)

In this generation new technologies are adopted to fabricate IC Chips. Such as electron beam x-rays and laser rays. The very large scale integration (VL5I) was developed so the computer beccrne much smaller than ever before. New memory storage devices like bubble memory and optical memory are being designed. The new computers will be controlled by using human voice and will work by giving command in our own languages Future computer will in some way to be intelligent and capable of making decisions

Advantage of Fifth Generadon

(1) Very large storage capacity.
(2) Long bit processor oullds.
(3) Artificial intellgence language developed

Disadvantages of Fifth Generation

No Demerits reported yet

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Basic Types of monitor

The two basic types of monitors are:

(1) CRT monitor, which is similar to the television screen and also work in the same way at uses a large vacuum tube called Cathode Ray Tube (CRT).
(2) Flat Panel Display (Liquid Crystal Display or LCD) which is usually used with portable computers but now have become very popular with the desktop computers too

Types Of Monitor (colour wise):

There are two types of monitors.

(1) Monochrome
(2) Gray-Scale
(3) Colour

(1) Monochrome: 

Monochrome monitors actually display two colours, one for the background and one for ~;.e fore ground. The colours can be black and white, green and black or amber and black

(2) Gray-Scale

A Gray-scale monitor is a special type of monochrome monitor capable of displaying different shades of gray

(3) Colour:

Colour monitors can display any where from 16 to over 1 million different colours.

Q.5 What do you mean by pointing devices? discuss on joystick?

Pointer Devices:


The elements of a computer system which can enter the data into computer arc called Input Devices

There are many Input devices of computer some of them are as follows.
(1) Keyboard
(2) Mouse
(3) Track ball
(4) Light Pen
(5) Joy Stick
(6) Magnetic Ink Recorder (MIR)
(7) Optical Character Read (OCR)
(8) Scanners
(9) Voice Synthesizer

(1) Keyboard
Keyboard is a device which is used to feed data into the computer. It looks like a typewriter.
(2) Mouse
Mouse is an input device which is used to various options or to draw
(3) Track Ball
A track ball is a pointing device the function of track ball is same as mouse. It is guided by the fingers instead of rolling on the desktop.
(4) Light Pen
Light pen is used in engineering designing we can draw fine quality pictures with the help of light pen.
(5) Joy Stick
A joystick is an input device used only to play computer games. It controls the movement of a certain object on the screen.
(6) Magnetic Ink Reader MIR
In MIR data is written in specified character set by magnetic ink and
the computer has given the ability to read it.
(7) Optical Character Read (OCR)
Optical character recognition devices are designed to read sheets of
papers, cards, books or journal tapes.
(8) Scanners
A scanner convert graphics and pictorial data to digital (binary) form
which can be directly feuded (stored) in computer.
(9) Voice Synthesizer .
It is the latest input device in which data is input by actual talking to
this computer

What is DOS? why is called Disk Operating system.


Dos stands for “Disk Operating System”. A disk operating system stores data on a Floppy disk or Hard disk.

Advantages of Dos

(1) It manages the routine work of computer system controlling everything from internal memory,
(2) It controls external communication.
(3) It manages the information on the disk.
(4) It controls the hardware of computer e.g. Monitor Display, Keyboard Input,
(5) It runs the computer programs.



The process of loading the Disk Operating System into the memory is called boot strapping or booting the system.

After loading the computer with DOS operating system the characters “C:/>” appearing on the screen is called DOS Prompt. DOS Prompt is a signal to the user that th computer is ready to be used. The letters “C”, “0”, “E” refer to the hard disk drives partitions. The letters “A” or “8” are used for Floppy disk drives. The last letter of the series is used for CD-ROM. The ‘/iigrf greater than ‘>’ fs a promor.

(3) Changing the default disk drive

Suppose after the booting from hard disk the active drive is C. tv change the disk drive from “C” to Floppy drive A.
(1) Type “A:” at the C Prompt
(2) Press the Enter Key.
C;:/> A: J (Symbol for Enter Key)

(4) file
All the work and programs are stored in the form of files on storage

(5) Numing file
Each file must have a me name which can be a combination of letters and members. File name consists of two parts. .
(i) The name (ii) The extenuon

Q.7 What is Machine language ? Discuss on its importance.

 Machine language

Every creation of this universe has its own language. like wise. computer has a language that is called Machine language (machine level language) for instructing computer to perform specific task. It is also called binary language because It is the language of Os and Is (zero and ones), means every instruction In Machine language cconllistsof a series of Os and 15 (binary eede): that Ii computer can understand and execute directly.

Each machlne language st atcment corresponds to one machine action. An operation that requires one machine language instruction in one computer may require several instruction. In another computer. EOld1 computer has iu own unique machine language

Machine Language Advantages 

(1) Machine language is highly suited for small computers which have the limited memory.
(2) Programs which are written in the machine language are quite efficient because it takes shortest time for execution as compared to those programs which are written in other language.
(3) No need of translation of the programs because those program which are written in machine language are directly understood by the computer

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Section “C” Detailed Question Answer

Q.17(a) Write dawn the Function of A.I.U and C.U Draw the block diagram of computer.

Arithmetic and Logic Unit (ALI)

This part of CPU is capable of performing arithmetic ant logic operations. It performs the arithmetic operations such as addition. subtraction. multiplication and division. It can also perform logical operations like comparing two numbers to see which number is greater than. less than or equal to another number.

The ALU performs millions of calculations and comparisons at a very high speed.

Control Unit

This pan of CPU monitors and complete computer system. It does not execute the instructions itself, it directs other porta of the computer system to do so. In simple words it controls the flow of data ..inside the computer. 

Block diagram of Computer

block diagram

block diagram

(b) Define Secondary Storage Devices. Write down the function of magnetic disk or magnetic devices

Secondary Storage Devices:

In Computers, the darn or information to be stored in an area from where it could be retrieved quickly and correctly. The ideal storage place for this huge amount of data would have been the computer memory. However computer memory despite being very large, it rather too much limited for this purpose. Some times it is impossible for a computer to retain such a huge information in its memory permanently. Therefore, this information is stored on external devices. This storage is called secondary storage and the devices used for this purpose are called backing storage devices or secondary storage devices. There are number of such devices available. The commonly used devices are

(i) Cassettes
(ii) Magnetic Tapes
(iii) Magnetic Disks

Magnetic Tapes:

For answer see Solved Paper Computer 2011 Q.18(b)(iii)

Magnetic Disks

For answer see Solved Paper Computer 201- Q.l ::(b)(ii)

Q.18(a) Write the main steps involve in the program solving process?

steps involve in the program solving process

All problems are solved through the following steps

Define the Problem

The first step in solving a problem Is to understand and define that problem i.e., what Is the purpose of the program? What data is to be processed? What output is required? What ls the input

Solve the Problem

Keeping the algorithm in mind. a program I. written to solve a problem

Because an algorithm enable. the computer to solve a problem, 10 algorithm should be designed carefully.

Drawing flowchart

Flowchart is nothing, but a pictorial representation of an algorithm. It is better to meet any problem with the help of a flowcharts.

Program Coding

Program coding la the process of writing instruction. in the appropriate programming language. Once the problem i. well defined then an algorithm represented by a flowchart is quite easily convened into an appropriate programming language.

Testing And Debugging

Testing and Debugging are the vital steps in developing computer programs. Testing is the process of making sure that t he program performs correctly and desired output would be achieved. Debugging is the process of locating and eliminating the errors.


Documentation is the process of recording details concerning a computer program. It usually contains many comments lines and many descriptions of how the program works. The documentation can be used in future to modify the program or remove errors

Discuss variable and contact with their example.


A constant is a simple fixed number that can be assigned to a variable in a program. There ace two types of constants.
(1) Numeric Constants
(2) String Constants

Numeric Constant

A numeric constant contains a number value that is assigned to a variable. Some of the valid numeric: constants are. as following 8.56. 784668+0.55-34 etc

String Consunts

String constant js a non-numeric value that can only be assigned to the string variable discussed later. In string constants, we can write any combination of chacacters enclosed in quote For example “AU”, “AYESHA”,”PAKISTAN’, ·042-5758561″ eee


As opposed to a constant. the value of a variable does not remain fixed. In every program written in BASIC, variable name. need to be used since the values associated with a variable name can be different at different times.
The two type. of variable. are discussed below

Numeric Variables

Those memory location. in which we can store only numbers ace called Numeric Variables

String Variables

Those memory locations in which we can store all the characters (i.e. letters. numbers, special characters) are known as string variables.

Q.19(a) Discuss on Direct and in-direct modes of basic language.
(b) Write short note on any one Three of the following

Hybrid computer

For answer see Solved Paper Computer 2012, Q.17(b)(iil)

Standard Alphanumeric

These keys (English Alphabets and Special Characters) are similar to a standard type writer and arc used for the input of general information.

Computer memory

This part of CPU stores data for using it again and again whenever it is required. A computer performs operations on program instruction and data stored in the main memory. The main memory is also called Primary Storage. internal storage or simply Memory.
The memory of a computer has two basic parts.
(1) Read Only Memory (ROM)
(2) Random Access Memory (RAM)

Basic Language

BASIC stands for Beginners All purpose Symbolic Instruction Code. As the name indicates BASIC language is relatively easier than other languages for beginners in computer. The reason is that the structure of the language is very simple to understand and programs in this language could be written after attending just a few introductory lectures.

GOTO statem

The GOTO is a branching statement It breaks the normal sequential execution and transfers the control from one part ~f the program to another. This type of transfer of control IS unconditional.

Line no, GOTO line no
10 print “ABC”
20 print “XYZ”
30 GOTO 10

Posted on December 21, 2015 in 10th Class 2013 Karachi Board Past Papers

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