O level computer question & answers


1)      Explain the difference between the binary number system and the denary number system?

-           A binary number system is a base- 2 number system which uses values from 0 to 1 whereas a denary number system uses values from 0 to 9.

-          Units in the binary number system is increased by a power of 2 whereas units in the denary number system increases by the power 10.

-          For the same value, the binary number system uses more digits as compared to denary number system.


2)      Explain what is meant by HTML?

HTML stands for hypertext markup language. It is used to create webpages. It is translated by a browser to display webpages to the user.

3)      Describe what is meant by structure and presentation?

Structure – refers to the layout of the context being displayed.

Presentation refers to the formatting of the content such as content color/style.

4)      Explain the function of the web browser?

A web browser is used to display web pages by interpreting and translating a HTML document. It also provides functions such as bookmarking webpages and saving webpage URL’s in its history.

5)      What are the uses of hexadecimal system?

Memory dumps


MAC addresses

Web Addresses (ASCII codes)

Assembly code / machine code

6)      What does the first and last six digits of the MAC address represents?

First six digits – manufactures ID

Last six digits – serial ID

7)       State why MAC addresses are used?

 To uniquely identify a device connected to the internet.

8)      Name three busses found in the Von Neumann architecture

-          Address bus

-          Data bus

-          Control bus

9)      Name the registers found in the Von Neumann architecture

-          Memory address register (MAR)

-          Memory data register (MDR)

-          Arithmetic and logic unit (ALU)

-          Program counter (PC)

-          Current Instruction register (CIR)

10)   What is the function of the control unit?

The control unit is part of the computer’s CPU and is responsible for processor, memory and I/O operations. It interprets a program’s instructions and then sends signals to the computer’s memory, arithmetical logical unit and input/output devices telling them what to do.

11)    -      Address bus – this uni-directional bus carries signals relating to memory addresses between processor and memory.

-          Control bus – this bus carries signals used to coordinate the computers activities.

-          Data bus – this bi-directional bus is used to exchange data between processor, memory and input/output devices.

12)   What is an interrupt?

It is a signal sent from a device to the


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