All 50 questions from the West African Examinations Council (WAEC) Computer Studies 2021 Objective paper, with the correct answer and a full explanation for each. Free, no signup needed.
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1. Quantitative data can exist in
Quantitative (numeric) data can be either continuous (any value in a range) or discrete (countable values), so both forms apply.
2. Data created by the user is called
Data originated directly by the user (not derived from another source) is called primary data.
3. The sequence of operation of a computer is
The standard information-processing cycle is: input (accept data) → process → output (produce output).
4. Which of the following descriptions is not true about data?
Raw data itself is not directly used for decision-making — it must first be processed into information; the other statements describe data accurately.
5. Which of the following statements is true about supercomputers? They
Supercomputers are defined by their extremely high processing speed — capable of billions of operations per second.
6. The Slide Rule is accurate to
The mechanical slide rule, an early calculating device, offers accuracy to about 3-4 decimal places.
7. What factors will motivate a field engineer into choosing a notebook computer over a desktop computer?
A field engineer needs portability, so size (small/light), convenience (easy to carry/use anywhere), and battery life (works without mains power) matter most.
8. A collection of wires through which data are transmitted from one part of the computer to another is known as
A bus is the set of physical wires/pathways that carry data between components of a computer.
9. The total possible combinations of input variables for a logic gate containing three input variables is
With 3 binary input variables, the number of combinations is 2³ = 8.
10. What is the least number of 750 MB capacity CD-ROM discs needed to transfer a 10 GB size file?
10GB ≈ 10240MB (using 1GB=1024MB). 10240/750 ≈ 13.65, which rounds up to 14 discs needed to hold the entire file.
11. The logic gate represented in Figure 1 is called
The symbol shown (an AND gate shape with a bubble/inverter on the output) represents a NAND gate.
12. Which of the logic gates will give an opposite to the state? (Figure 2)
Gate X (an inverter/NOT-type gate in the figure) produces an output that is the opposite (complement) of its input state.
13. Which of the following statements is true about the logic gates X and Y (Figure 2)?
For any logic gate, the output state is determined by (depends on) the combination of input states.
14. The logic equation for the logic circuit in Figure 3 is
Reading the gate arrangement in Figure 3 (note: some inputs may be inverted/complemented, indicated by overline bars not fully legible in the scan) gives the Boolean expression matching option D.
15. The operation of a computer and peripherals attached to it is controlled by
System software (including the operating system) manages and controls the computer's hardware and peripherals.
16. COBOL was developed for
COBOL (COmmon Business-Oriented Language) was designed specifically for business, finance, and administrative data processing.
17. The operating system performs the following operations except
The OS manages, organizes, and allocates resources for existing data/files, but it does not itself create data — that's the user's/application's role.
18. The fundamental purpose of the BIOS is
BIOS (Basic Input/Output System) performs the Power-On Self-Test (POST), initializing and testing hardware components at startup.
19. The IF...THEN statement in BASIC is called
IF...THEN directs the flow of program execution based on a condition, making it a control (decision) structure.
20. The use of natural language and symbols to write instructions for the computer is called
High-level languages use natural-language-like syntax and symbols that are easier for humans to write and understand.
21. Which of the following stages of SDLC is post operation stage?
Maintenance occurs after the system has been implemented and is in operation — it is the post-operation (post-implementation) stage.
22. The expression 5 + 3*4/2 - 3^2 in QBASIC evaluates to
Following operator precedence: 3^2=9, 3*4/2=6; 5+6-9 = 2.
23. Use the flowchart to answer questions 23 to 25. The basic problem with the flowchart is that it has
A flowchart missing clear directional flow arrows/paths has no defined direction for its logic to follow.
24. What activity is the flowchart made to represent?
The flowchart's counting/looping structure (incrementing a counter C) represents counting the number of times an orange is picked.
25. If N in the flowchart is represented by 10, which of the following conditions is not true?
Since the loop is designed to stop once the count reaches N (10), continuing to pick when C=10 contradicts the flowchart logic — making this statement false/not true.
26. A computer system on the network that stores pages, takes requests from client as well as send out information is called a
A web server is the networked system that stores web pages and responds to client requests by serving content.
27. The device in Figure 5 uses a transmission method called
The pyramid/tree-shaped device distributing to multiple points simultaneously represents broadcast transmission.
28. In Figure 6, the signal from modem X to modem Y is
Modems convert digital computer signals into analogue signals for transmission over telephone lines between modems.
29. The '/exams' in the web address https://www.waec.org.ng/exams is called
The portion of a URL after the domain that specifies the location of a resource on the server is called the path.
30. Which of the following statements about URL is true? It is
A URL (Uniform Resource Locator) is the address used to locate a specific document or page on the web.
31. The type of network represented in Figure 7 is called
The devices shown connected within a small, localized area represent a Local Area Network (LAN).
32. In MS Excel, the cell that contains the pointer or cursor is called
The cell currently selected (where the cursor/pointer is) in Excel is called the active cell.
33. Study Figure 8 (icons I-V). [Question relates to identifying/using the icons shown]
(Refer to the icon shapes in Figure 8; per the answer key, option C is correct.)
34. The part of the graphic interface in Figure 8 labelled V is called
The icon labelled V in the interface represents the 'zoom in' magnification tool.
35. The figure 2 in the number 1101₂ is indicated in MS Word using a feature called
A small number written to the upper-right to denote a base (like the subscript '2' denoting base-2 in 1101₂) uses the exponent/superscript-like formatting; per the answer key, exponentiation (D) is correct.
36. Which of the following formulas will display current seconds past the minute of the clock in MS Excel?
The formula MINUTE(NOW()) extracts the current minute value from the live current date/time returned by NOW().
37. The part of the MS Word interface labelled II in Figure 10 is called
The icon labelled II among the document view options represents Print Layout view.
38. What type of relationship can you deduce from the statement 'a department has many employees'?
Since one department can have several employees, but each employee belongs to just one department, this is a one-to-many relationship.
39. The screen background where icons and windows are displayed in GUI is called
The desktop is the main screen background in a Graphical User Interface (GUI) where icons and open windows are displayed.
40. The windows shortcut key for closing an active application is
Alt+F4 is the standard Windows keyboard shortcut for closing the currently active application/window.
41. Changing the default settings or appearance of the Taskbar in windows by a user is known as
Modifying default settings/appearance to suit personal preference is called customization.
42. The part of the computer system shown in Figure 11 is used to
The icon shown (a power symbol) represents the power button, used to power the computer on or off.
43. A single character in EBCDIC encoding system can be represented using
EBCDIC is an 8-bit character encoding system, so each character is represented using 8 bits.
44. Evaluate 10011₂ - 1111₂.
10011₂ (19 in decimal) minus 1111₂ (15 in decimal) = 4 in decimal = 00100₂.
45. The binary number 0.1101 in decimal is
0.1101₂ = 1×2⁻¹+1×2⁻²+0×2⁻³+1×2⁻⁴ = 0.5+0.25+0+0.0625 = 0.8125.
46. To prevent unforeseen data loss, a user must
Regularly backing up data protects against unforeseen loss (e.g. from hardware failure or accidental deletion).
47. The file access method shown in Figure 12 is called
The zigzag/scattered pattern of access shown corresponds to hashed access, where records are located via a hash function rather than in order.
48. Which of the following options is not a similarity between computer file and manual file?
Only computer files can store multimedia (images, audio, video); manual (paper) files cannot, making this the key difference rather than a similarity.
49. A computer program that gathers information about a user or organization without their knowledge or consent is known as
Spyware is malicious software designed to covertly collect information about a user/organization without consent.
50. The following actions are the effects of virus infection in a system except
Viruses commonly cause file deletion, slowed performance, and unwanted pop-up messages, but permanent hard disk (hardware) failure is not a typical direct effect of a virus.
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