JAMB Past Questions

JAMB Computer Studies 2021
Questions & Answers

40 questions · Correct answers highlighted · 40 with explanations

40 Total Questions
2021 Exam Year
40 With Explanations
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1
Question 1 of 40
JAMB · Computer Studies · 2021

Which of the following devices is used to convert analog signals to digital signals?

A. Router
B. Modem
C. Switch
D. Hub
Explanation

A modem converts analog signals to digital signals and vice versa, enabling internet connectivity by translating signals between a computer and an ISP. Option B is correct.

2
Question 2 of 40
JAMB · Computer Studies · 2021

What is the decimal equivalent of the binary number 1101?

A. 11
B. 12
C. 13
D. 14
Explanation

To convert 1101 to decimal: (1×2³) + (1×2²) + (0×2¹) + (1×2⁰) = 8 + 4 + 0 + 1 = 13. Option C is correct.

3
Question 3 of 40
JAMB · Computer Studies · 2021

Which of the following is a feature of third-generation computers?

A. Vacuum tubes
B. Integrated circuits
C. Transistors
D. Microprocessors
Explanation

Third-generation computers (1964–1971) used integrated circuits, improving efficiency and size over transistors (second-generation). Option B is correct.

4
Question 4 of 40
JAMB · Computer Studies · 2021

In programming, what is the purpose of a loop?

A. To make decisions
B. To repeat a block of code
C. To store data
D. To call functions
Explanation

A loop repeats a block of code until a condition is met, such as ‘for’ or ‘while’ loops, enabling repetitive tasks. Option B is correct.

5
Question 5 of 40
JAMB · Computer Studies · 2021

Which of the following is an example of application software?

A. Linux
B. Microsoft Excel
C. Windows XP
D. Device drivers
Explanation

Microsoft Excel is application software for user tasks, unlike system software (Linux, Windows XP) or drivers. Option B is correct.

6
Question 6 of 40
JAMB · Computer Studies · 2021

What does the acronym BIOS stand for?

A. Basic Input/Output System
B. Binary Input/Output System
C. Basic Internal Operating System
D. Binary Internal Operating System
Explanation

BIOS (Basic Input/Output System) initializes hardware during boot and provides runtime services. Option A is correct.

7
Question 7 of 40
JAMB · Computer Studies · 2021

Which of the following is used to create a webpage’s structure?

A. CSS
B. HTML
C. JavaScript
D. PHP
Explanation

HTML (HyperText Markup Language) defines a webpage’s structure, while CSS styles, and JavaScript/PHP add interactivity or server-side functions. Option B is correct.

8
Question 8 of 40
JAMB · Computer Studies · 2021

The hexadecimal equivalent of the decimal number 10 is:

A. A
B. B
C. C
D. D
Explanation

In hexadecimal, decimal 10 is A, as it uses base-16 (0–9, A–F for 10–15). Option A is correct.

9
Question 9 of 40
JAMB · Computer Studies · 2021

Which of the following is a function of an assembler?

A. Converts high-level code to machine code
B. Converts assembly code to machine code
C. Executes programs directly
D. Debugs program errors
Explanation

An assembler translates assembly language (low-level) into machine code for execution. Option B is correct.

10
Question 10 of 40
JAMB · Computer Studies · 2021

What is the purpose of a foreign key in a database?

A. To uniquely identify records
B. To link tables
C. To sort data
D. To encrypt data
Explanation

A foreign key links tables by referencing a primary key, ensuring data integrity. Option B is correct.

11
Question 11 of 40
JAMB · Computer Studies · 2021

Which of the following is a non-volatile storage device?

A. RAM
B. Cache
C. Flash Drive
D. Registers
Explanation

A flash drive retains data without power (non-volatile), unlike RAM, cache, or registers (volatile). Option C is correct.

12
Question 12 of 40
JAMB · Computer Studies · 2021

In networking, what does WAN stand for?

A. Wireless Access Network
B. Wide Area Network
C. Wired Access Network
D. Web Application Network
Explanation

WAN (Wide Area Network) connects devices over large areas, like the internet. Option B is correct.

13
Question 13 of 40
JAMB · Computer Studies · 2021

Which of the following is a valid data type in Python?

A. Integer
B. Character
C. Real
D. Double
Explanation

Python uses Integer (int), String (str), Float, etc., but not Character, Real, or Double as distinct types. Option A is correct.

14
Question 14 of 40
JAMB · Computer Studies · 2021

What is the role of a switch in a network?

A. To connect different networks
B. To forward data to specific devices
C. To convert signals
D. To store network data
Explanation

A switch forwards data to specific devices in a LAN based on MAC addresses. Option B is correct.

15
Question 15 of 40
JAMB · Computer Studies · 2021

Which of the following is an output device?

A. Scanner
B. Keyboard
C. Monitor
D. Mouse
Explanation

A monitor displays visual output, unlike scanners, keyboards, or mice (input devices). Option C is correct.

16
Question 16 of 40
JAMB · Computer Studies · 2021

What does SQL stand for in database management?

A. Structured Query Language
B. Standard Query Language
C. Simple Query Language
D. Systematic Query Language
Explanation

SQL (Structured Query Language) manages relational databases for data manipulation. Option A is correct.

17
Question 17 of 40
JAMB · Computer Studies · 2021

The binary equivalent of the hexadecimal number B is:

A. 1010
B. 1011
C. 1100
D. 1101
Explanation

Hexadecimal B is decimal 11. Binary: 11 ÷ 2 = 5 remainder 1, 5 ÷ 2 = 2 remainder 1, 2 ÷ 2 = 1 remainder 0, 1 ÷ 2 = 0 remainder 1, so 1011. Option B is correct.

18
Question 18 of 40
JAMB · Computer Studies · 2021

Which of the following is a characteristic of a relational database?

A. Data stored in hierarchical structure
B. Data organized in tables
C. Data stored as objects
D. Data stored in a single file
Explanation

Relational databases organize data in tables linked by keys, unlike hierarchical or object-oriented databases. Option B is correct.

19
Question 19 of 40
JAMB · Computer Studies · 2021

What is the purpose of a flowchart in programming?

A. To write code
B. To debug programs
C. To represent algorithms visually
D. To compile code
Explanation

A flowchart visually represents algorithms using shapes for steps and decisions, aiding planning. Option C is correct.

20
Question 20 of 40
JAMB · Computer Studies · 2021

Which of the following is a protocol for sending emails?

A. HTTP
B. FTP
C. SMTP
D. TCP
Explanation

SMTP (Simple Mail Transfer Protocol) sends emails, unlike HTTP, FTP, or TCP. Option C is correct.

21
Question 21 of 40
JAMB · Computer Studies · 2021

Which of the following is a feature of a spreadsheet?

A. Word processing
B. Data calculation
C. Image editing
D. Code compilation
Explanation

Spreadsheets (e.g., Excel) enable data organization and calculation with formulas. Option B is correct.

22
Question 22 of 40
JAMB · Computer Studies · 2021

What is the octal equivalent of the decimal number 25?

A. 30
B. 31
C. 32
D. 33
Explanation

Convert 25 to octal: 25 ÷ 8 = 3 remainder 1, so 31. Option B is correct.

23
Question 23 of 40
JAMB · Computer Studies · 2021

Which of the following is a low-level programming language?

A. Python
B. Java
C. Assembly
D. C++
Explanation

Assembly uses mnemonic codes, closer to machine code than high-level languages like Python or Java. Option C is correct.

24
Question 24 of 40
JAMB · Computer Studies · 2021

What is the role of an interpreter in programming?

A. Converts code to machine language at once
B. Executes code line by line
C. Debugs syntax errors
D. Compiles code into an executable file
Explanation

An interpreter executes high-level code line by line, unlike a compiler. Option B is correct.

25
Question 25 of 40
JAMB · Computer Studies · 2021

Which of the following is a type of computer virus?

A. Trojan
B. Firewall
C. Router
D. Browser
Explanation

A Trojan is malware disguised as legitimate software, unlike firewalls, routers, or browsers. Option A is correct.

26
Question 26 of 40
JAMB · Computer Studies · 2021

What does RAM stand for in computer hardware?

A. Random Access Memory
B. Read-Only Memory
C. Rapid Access Module
D. Remote Access Memory
Explanation

RAM (Random Access Memory) is volatile memory for temporary data storage. Option A is correct.

27
Question 27 of 40
JAMB · Computer Studies · 2021

Which of the following is used to style a webpage?

A. HTML
B. CSS
C. JavaScript
D. SQL
Explanation

CSS (Cascading Style Sheets) styles webpage appearance, such as colors and layouts. Option B is correct.

28
Question 28 of 40
JAMB · Computer Studies · 2021

In binary arithmetic, 110 - 11 equals:

A. 011
B. 100
C. 101
D. 111
Explanation

Convert to decimal: 110 = 6, 11 = 3. Subtract: 6 - 3 = 3. Convert 3 to binary: 011. Alternatively, binary subtraction: 110 - 011 = 011 (borrow from higher bits). Option A is correct.

29
Question 29 of 40
JAMB · Computer Studies · 2021

Which of the following is a feature of a GUI?

A. Text-based commands
B. Graphical icons and windows
C. Manual hardware configuration
D. Command-line interface
Explanation

A GUI uses graphical icons, windows, and menus, unlike text-based interfaces. Option B is correct.

30
Question 30 of 40
JAMB · Computer Studies · 2021

What is the purpose of a backup in computing?

A. To increase processing speed
B. To recover data after loss
C. To compile programs
D. To connect networks
Explanation

A backup restores data lost due to failures or attacks. Option B is correct.

31
Question 31 of 40
JAMB · Computer Studies · 2021

Which of the following is an example of a web browser?

A. Microsoft Word
B. Google Chrome
C. Notepad
D. Excel
Explanation

Google Chrome is a web browser for accessing websites, unlike Word, Notepad, or Excel. Option B is correct.

32
Question 32 of 40
JAMB · Computer Studies · 2021

What is the function of a cache memory?

A. To store permanent data
B. To speed up data access
C. To connect networks
D. To execute programs
Explanation

Cache memory stores frequently accessed data to reduce access time, boosting CPU performance. Option B is correct.

33
Question 33 of 40
JAMB · Computer Studies · 2021

Which of the following is a server-side programming language?

A. JavaScript
B. CSS
C. PHP
D. HTML
Explanation

PHP processes requests on the server for dynamic content, unlike JavaScript (often client-side), CSS, or HTML. Option C is correct.

34
Question 34 of 40
JAMB · Computer Studies · 2021

What is the smallest unit of digital information?

A. Byte
B. Bit
C. Nibble
D. Kilobyte
Explanation

A bit (0 or 1) is the smallest unit of digital information. Option B is correct.

35
Question 35 of 40
JAMB · Computer Studies · 2021

Which of the following is a characteristic of a supercomputer?

A. Low processing power
B. High-speed computation
C. Limited memory
D. Single-user system
Explanation

Supercomputers perform high-speed computations for scientific research. Option B is correct.

36
Question 36 of 40
JAMB · Computer Studies · 2021

What does FTP stand for in networking?

A. File Transfer Protocol
B. Fast Transmission Protocol
C. File Tracking Protocol
D. Functional Transfer Protocol
Explanation

FTP (File Transfer Protocol) transfers files between computers on a network. Option A is correct.

37
Question 37 of 40
JAMB · Computer Studies · 2021

Which of the following is a type of operating system?

A. Microsoft Word
B. Ubuntu
C. Google Chrome
D. Adobe Photoshop
Explanation

Ubuntu is a Linux-based operating system, unlike the other application software options. Option B is correct.

38
Question 38 of 40
JAMB · Computer Studies · 2021

In a flowchart, the parallelogram shape represents:

A. Process
B. Decision
C. Input/Output
D. Start/Stop
Explanation

A parallelogram in a flowchart represents input/output operations, like reading or displaying data. Option C is correct.

39
Question 39 of 40
JAMB · Computer Studies · 2021

Which of the following is used to query a database?

A. HTML
B. SQL
C. CSS
D. JavaScript
Explanation

SQL queries and manages data in relational databases. Option B is correct.

40
Question 40 of 40
JAMB · Computer Studies · 2021

What is the purpose of an IP address?

A. To identify a device on a network
B. To encrypt data
C. To store files
D. To compile code
Explanation

An IP address uniquely identifies a device on a network for communication. Option A is correct.

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