1.Convert the Hexadecimal value 3A into Denary. Show your working.
Answer: 58
Working: (3 * 16) + (10 * 1) = 48 + 10 = 58. (1 mark for working, 1 for correct answer).
2.Explain why Hexadecimal is often used by programmers instead of Binary.
Answer: It is easier for humans to read/write, it is shorter/more concise, and it reduces the likelihood of errors when typing or reading code.
Key: Easier to read, shorter, fewer errors. Note: It does NOT take up less space in memory.
3.Describe the function of the Control Unit (CU) in the Von Neumann model.
Answer: It manages the flow of data through the CPU, decodes instructions, and sends control signals to other components (like the ALU or RAM).
Key: Sends control signals, decodes instructions, manages data flow.
4.What is the difference between MIDI and MP3 files?
Answer: MP3 is a lossy compressed format containing actual audio data/waves. MIDI contains instructions (pitch, volume, tempo) for a digital instrument to play sound; it contains no actual audio.
Key: MP3 = recorded sound data; MIDI = set of instructions/commands.
5.Identify two sensors used in a automated street lighting system.
Answer: Light sensor (LDR) and Motion/Infrared sensor.
Accept: Light/LDR, PIR/Motion.
Communication & Internet
6.Define 'Serial, Duplex' data transmission.
Answer: Serial: Bits are sent one at a time over a single wire. Duplex: Data can be sent in both directions simultaneously.
1 mark for Serial definition, 1 mark for Duplex (simultaneous).
7.Explain how Symmetric Encryption works.
Answer: The same key is used to both encrypt and decrypt the data. The key must be shared securely between sender and receiver.
Key point: Same key used for both processes.
8.What is the purpose of an 'Interrupt' in a computer system?
Answer: A signal sent to the processor to stop current task and handle a higher-priority request (e.g., hardware failure, user input, printer out of paper).
Key: Signal to CPU, priority handling, allows multi-tasking.
9.Briefly explain what 'Phishing' is.
Answer: A cyberattack where users receive fake emails/messages pretending to be from a legitimate source to trick them into revealing sensitive data like passwords.
Answer: Acts as an intermediary between a user and the internet. It can filter content, hide the user's IP address for security, and cache web pages to speed up access.
12.Identify two types of test data and explain what they are.
Answer: 1. Normal: Valid data the system expects. 2. Boundary: Data at the limit of what is acceptable. 3. Erroneous: Invalid data that should be rejected.
Accept any two of: Normal, Abnormal/Erroneous, Boundary/Extreme.
13.What is a 'Range Check'? Provide an example.
Answer: A validation check that ensures a value falls between a specific minimum and maximum. Example: Checking if an age is between 1 and 100.
Key: Validation, min/max limits.
14.Describe the structure of a 'WHILE' loop.
Answer: A pre-condition loop that repeats a block of code as long as a specified condition is True. If the condition is False at the start, the code never runs.
Key: Pre-condition, repeats while True.
15.Write the pseudocode to initialize an array named 'Marks' with 50 zeroes.
Answer:
FOR i ← 1 TO 50
Marks[i] ← 0
NEXT i
Correct loop bounds (1-50), correct assignment.
16.State the logic gate that outputs 1 ONLY when both inputs are 1.
Answer: AND Gate.
Must be AND.
17.Explain what 'Verification' is in the context of data entry.
Answer: Checking that data has been entered correctly without changes, usually by double-entry (typing twice) or visual check.
Note: Verification is NOT checking if data is sensible (that's validation).
18.What is the difference between a variable and a constant?
Answer: A variable's value can change during program execution. A constant's value is set at the start and cannot be altered while the program is running.
Key: Changeable vs Fixed.
19.Identify one advantage of using named Subroutines (Procedures/Functions).
Answer: Code reusability, easier to debug, reduces program length, or allows different programmers to work on different parts.
Accept any valid advantage.
20.Write the Truth Table output for a NOT gate.
Answer: Input 0 -> Output 1; Input 1 -> Output 0.
The gate inverts the input.
Test Complete! Compare your typed answers with the sample answers to gauge your readiness.