Computer (general group) Solved Past Paper 10th Class 2015 Karachi Board


Q.1 Choose the correct answer for each from the given options

(i) The main memory of computer is also called:
* External storage
* Primary storage
* Secondary storage
* All of these

(ii) Laptop computer is a type of computer:
* Analog
* Mini
* Digital
* None of these

(iii) It is a pictorial representation of a program.
* Algorithm
* Flowchart
* Source code
* None of these

(iv) This command is used to clear memory:
* Kill
* New
* Delete

(v) FOR-NEXTstatement is used for:
* Looping
* Branching
* Counting
* Printing

(vi) It is a memory location that holds the values during program execution.
* Variable
* Constant

(vii) Cobol language was developed in:
* 1959
* 1960
* 1969
* 1955

(viii) This DOS command gives a new name to a file:
* Name
* Ren
* New name
* All of these

(ix) It is the process of removing the errors.
* Erasing
* Deleting
* Kill
* Debugging

(x) Improved version of ENIACwas named:
* Mark-I

(xi) A collection of eight bits is defiried as:
* byte
* Nibble
* Word
* Character

(xii) Comma between variables divides the screen into zones with print statement:
* 10
* 8
* 5
* 9

(xiii) Equal ro(=) is a / an operator:
* Relational
* Logical
* Arithmetical
* None of these

(xiv) This command is used to make disk usable:
* Die
* Copy
* Format

(xv) The development of this is referred as solid
* Vacuum tube
* Transistor
* IC
* None of these


Q.2 Define loop and Counter loop?


A loop is a technique which executes an instruction or group of instruction repeatedly. It is also observed that a combination of IF and GOTO statement can also be used as a loop.

The following two types of loops are commonly used.
(1) Counter Loop (2) Controlled Loop

Counter Loop:

Counter Loop is used to execute a set of statements for a specific number of times. In BASIC, FOR NEXT. statement is used for this purpose

Q.3 Differentiate between Analog Computer and Digital Computer.

Difference b/w Analog and Digital Computers:

analog and digital

analog and digital

Q.4 Write the purpose of the following DOS commands:

(i) VER

It displays the DOS version number



(ii) DIR/W


Display directory in width-wise. Only file names are displayed  no other information is shown .





It copies the entire contents of a floppy disk to another formatted or unformatted floppy disk


Diskcopy [drivel: drive 2]

Q.5 What is Machine language? Discuss 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 Osand Is (zero and ones), means every instruction in Machine language consists of a series of Os and Is (binary code) that a computer can understand and execute directly.

Each machine language statement corresponds to one machine action. An operation that requires one machine language instruction in one computer may require several instructions in another computer. Each computer has its own unique machine language.

Importance of Machine Language

(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.

Q.6 Define Data and Information:

data information

data information

Q.7 Covert the following decimal numbers into their binary equivalent



Hence, the equivalent binary number is, (1111101111)²

Q.8 What are Reserved words? Explain.

Reserved Words

Reserved words ~e those words which can be useful for specific purposes. These words should not be used as variable names. There are different reserve words e.g. READ, PRINT, INPUT, IF, END, etc. The list of reserved names is given in appendix A.

Q.9 Convert the following Binary numbers into their Decimal equivalent,

Answer Question

Answer Question



Q.12 Convert the following algebric expressions into their Basic:formula:



Q.13 Define Input devices and output devices with examples

Input Devcies
The devices, which are used for entering data into the computer are called “Input Devices”. For example Keyboard, Mouse, Joystick etc.

Output Devcies
The devices, which are used to retrieve data or information from the computer are called “Output Devices”. For example Monitor, Printer etc

Q.14 What is Monitor? Explain


To display results or output from computer a T.V. like device is used and called Monitor. Monitor assists during input from the Keyboard. It also displays all normal and error messages. The displayed output is called a “Soft Copy” of Information.

The monitor and VDU is also known as CRT (Cathode Ray Tube) because it has an electronic tube. The electronic guns send beam of electronic to trace regular pattern if horizontal lines or data on the phosphor that coat the screen of surface.

Basic type of Monitor

The two basic types of monitors are: .
(1) CRT monitors which is similar to the television screen and also work in the same It 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.

Q.15 Draw and write the purpose of the following symbols of





Question Answer


Q.17(a) What is meant by Backing Storage devices? Define Magnetic tape and Magnetic disk.

Backing Storage Device
A huge amount of data cannot be loaded into RAM at a time, thus it becomes essential to use backing storage device to supplement the primary storage (RAM).

Magnetic Disk
A hard disk is a magnetic disk on which you can store data. It is a fixed storage media, although it is possible to buy removable hard disks. The term ‘hard’ is used to distinguish it from a soft or floppy disk. Hard disks contain several billion bytes (giga bytes) of storage in today’s computer. Hard disks are rigid aluminium or glass disks about 3.5″ in diameter in a personal computer and smaller in laptop. They are ferromagnetic material and a read/write head transfers data, to it magnetically. A hard disk is really a set of stacked “disks”. The surface of each disk is divided into a number of evenly spaced concentric circular tracks. The set of all tracks at a given radius on all surface are known as cylinder. Each track is divided into sectors.

Magnetic Tape
A magnetic tape is a storage device from which you can access data serially like an audio cassette from which you can hear the songs ill the order in which they are stored. Serial access is slower than the direct access provided by media such as diskettes. When you want to access some particular data from the tape, the device has to scan through all the data you do not need but the data is stored before the required one. The access speed can be quite slow when the tape is long and what you want is not near the start. So the best use of the magnetic tape is for the data that you do not use very often.

(b) What do you mean by High level language? Explain any
three high level languages

High Level languages:

The set of commands available in high level languages are very simple and easy to understand. High level languages are further divided into two major categories

Procedure Oriented languages

In this category we are able to create our projects or programs using procedural approach means in this type we can able to divide our big project program into small solutions or procedures. After making procedures we can able to call a procedure one or more places. The list of procedural languages are as follows: C language, C ++ (object oriented) and Pascal language etc

Non-Procedural Languages

This category also known as “Problem Oriented Languages”. In this type of languages we can able to make program only at specific range like database. The following are the examples of non-procedural languages.
(1) SQL (Structured Query Language)
(2) SNOBOL (String Processor)

Following are some high-level languages


BASIC stands for Beginner’s All-Purpose Symbolic Instruction Code. BASIC was developed by John G.Kemeney and Thomas E.Kurtz in the mid 1960s at Dartmouth College. BASIC is one of the earliest and simplest high-level programming languages.


FORTRAN is one of the oldest programming languages. FORTRAN was developed by a team of programmers at IBM led by John Backus and was first published in 1957. FORTRAN is an acronym for FORmula TRANslation, because it was designed to allow easy translation of math formulas into code.


The C++ programming langua~s is an extension of C that was developed by Bjarne Stroustrup ~he early 1980s at Bell Laboratories. C+ + provides a number of features that “spruce up” the C language. It provides capabilities for object-oriented programming .

Q.18(a) Draw the Generation Table.

Generation Table

Generation Table

(b) What is Keyboard? Describe the divisions of Keyboard.


In most computers, a key board is the primary text input device. It consists of a set of keys for computer input, which uses the same key arrangements as the mechanical and electronic typewriter Keyboards that produced the computer but with a few extra key for computer commands and usually with the addition of a numeric keypad. The standard arrangement of alphabetic keys is know as the QWERTY(Pronounced KWEHR-TEE) keyboard. The name is derived from the arrangement of five keys at the left of upper first row of alphabetic keys. A standard key board includes about 100 keys and each key sends a different signal to the CPU keyboards for personal computers that come in many different styles that differ in size, number of keys and shape

Division of Keyboard

Alphanumeric Keypad:

This is the main part of keyboard by using this keypad the letters a-z, A-Z, numbers 0-9 and special characters like !#$%/-+ etc may be typed. Many of these characters are typed by holding shift key. Any type of data can be entered through this keyboard

Numeric Keypad:

Numeric Keypad usually placed on the right hand side of the key board that looks like a simple calculator which includes number keys from 0 to 9 digits, the four basic operation (+, -, ., I), decimal point and Num Lock key that works similar to Caps Lock, to force the numeric keys to input numbers

Function Keypad

In the enhanced Keyboard, a set of twelve (keys marked as FI to FI2) is located at the top of the keyboards this function keypad is ‘located on the left with only ten keys. All of these keys have pre-defined meanings which depend on the application software.

Screen Navigation or Cursor Movement Keys

In many programs there is a blinking mark on the screen where the key you press will display a particular character/digit/Special character. This mark called cursor, appears indifferent shapes in various programs, a solid small box, a vertical line etc. cursor control keys are used to move the cursor around the screen. Most keyboards include the following Cursor Movement Keys.

(i) Arrow Keys
(ii) Home and END
(iii) Page up and page Down

Modifier Keys:

These keys are used to modify the input of other keys. Your press another key while holding down one of the modifier keys, shift, ctrl, alt are same examples of modifier keys

(i) Delete Keys
(ii) Insert key
(iii) Esc Key
(iv) Print Screen Keys

Q.19(a) What are the main steps involved in the solution of a
program? Explain,

Steps to Solve a Program

Whenever we want to solve a problem through the computer, before programming we require two specifications. The first will detail the precise problem to be solved and the type of the information which is required. The second will itemize the computer configuration which will handle the job, i.e, the available equipment. This whole process is known as Problem Analysis.

We know su\nmarize these steps which a programmer is concerned in the development of a program, from the specification of the problems to its successful completion. The programming process is a problem solving process and it consist of the following steps

1) Defining the problem
(2) Analysis of the problem
(3) Algorithm
(4) Coding
(5) Implementation

Write short note on


Mouse is also a primary input device but lacks the ability to easily transmit actual information. It is called pointing device that is used to move a pointer on the computer screen in order ‘to point to a place on a display screen and to select one or more actions to be taken for the position


This part of CPU is capable of performing arithmetic and 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

Hybrid Computer

The hybrid computers combine the characteristics and advantages of both digital and analogue computers. They have the speed of Analogue computers and the accuracy of digital ~computers and being equipped with special conversion devices, its utilities both analogue and discrete representation of data. For example speed of Analogue computer and memory and accuracy of digital computers.


Posted on December 18, 2015 in 10th Class 2015 Karachi Board Past Papers

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