Computer Engineering practice questions (Jahziah exam)

Area 01 · Circuits & electronics

A 12 V battery is connected across a resistor and the current through it is measured to be 3 mA. What is the resistance of the resistor?

1. A250 Ω
2. B4 Ω
3. 4 kΩ
4. D36 kΩ

Sample — the full set, with spaced review and mocks, is in the app.

Area 02 · Computer architecture & organization

A system has a 4-way set-associative cache organized into 64 sets, with a block size of 32 bytes. How many bits are used for the set index field of a 32-bit memory address?

1. A5 bits
2. 6 bits
3. C11 bits
4. D7 bits

Sample — the full set, with spaced review and mocks, is in the app.

Area 03 · Digital design

A 4-to-1 multiplexer has data inputs D0 = 0, D1 = 1, D2 = 0, D3 = 1 and select lines S1, S0 with S1 as the most significant bit. The output Y is taken from the multiplexer. An engineer claims: 'Y = S0 for every combination of the select lines.' Determine the actual value of Y for each combination of (S1, S0) and decide whether the claim is correct.

1. Y = 0, 1, 0, 1 for (S1,S0) = (0,0), (0,1), (1,0), (1,1); the claim is correct.
2. BY = 0, 1, 0, 1 for (S1,S0) = (0,0), (0,1), (1,0), (1,1); the claim is false, because Y also equals S0 only coincidentally and is not defined by S0.
3. CY = 1, 0, 1, 0 for (S1,S0) = (0,0), (0,1), (1,0), (1,1); the claim is false.
4. DY = 0, 1, 1, 0 for (S1,S0) = (0,0), (0,1), (1,0), (1,1); the claim is false.

Sample — the full set, with spaced review and mocks, is in the app.

Area 04 · Embedded systems

An engineer uses a UART in 8N1 mode at 9,600 bps. If the receiver samples at 16× the bit rate, how many sampling clock cycles occur in one complete transmitted character frame?

1. A128
2. B144
3. 160
4. D176

Sample — the full set, with spaced review and mocks, is in the app.

Area 05 · Computer networks

Three wireless architectures are described for a moving terminal that must keep a continuous voice session while roaming over a wide area: (i) a cellular network with a home location register and visitor location registers, (ii) an infrastructure Wi-Fi network using a single extended service set with one SSID, and (iii) a Bluetooth piconet. Which statement correctly contrasts their support for wide-area mobility?

1. AAll three provide equivalent wide-area mobility because each uses a unique device address for routing.
2. The cellular network supports wide-area roaming through location registers and inter-cell handoff, while the Wi-Fi extended service set and the Bluetooth piconet are limited to local coverage and lack inter-network location management.
3. CThe Bluetooth piconet provides the widest coverage because its master can hand a connection to any other piconet without prior registration.
4. DThe Wi-Fi extended service set provides wide-area mobility because all access points use the same SSID and therefore share one global location register.

Sample — the full set, with spaced review and mocks, is in the app.

Area 06 · Systems resource management

A process issues a read system call for data not currently in main memory. Which sequence of hardware and operating-system actions correctly completes this request?

1. AThe process reads the disk directly, then the OS invalidates the page table entry.
2. The MMU raises a page-fault exception, the OS saves the process state, loads the missing page into memory, updates the page table, and restores the process state to resume the instruction.
3. CThe cache controller loads the page from disk and continues execution without involving the OS.
4. DThe OS stalls the CPU until a direct-memory-access controller copies the whole process address space to memory.

Sample — the full set, with spaced review and mocks, is in the app.

Area 07 · Signal processing

Two finite-length discrete-time sequences are x[n] = {1, 2} for n = 0, 1 and h[n] = {3, 4} for n = 0, 1, and both are zero elsewhere. Their linear convolution y[n] = x[n] * h[n] has how many nonzero samples, and what is the value of y[2]?

1. A3 nonzero samples, and y[2] = 10
2. 3 nonzero samples, and y[2] = 8
3. C4 nonzero samples, and y[2] = 8
4. D3 nonzero samples, and y[2] = 11

Sample — the full set, with spaced review and mocks, is in the app.

Area 08 · Systems & project engineering

An engineering team interviews users for a new traffic-light controller. The users say the controller should 'switch phases when the road is empty.' The requirements document simply writes: 'The controller shall switch phases when the road is empty.' Which method most appropriately derives a precise system specification from this vague requirement?

1. AAdd the statement to the functional requirements list without changes so it stays traceable to the user.
2. BReplace the word 'empty' with 'when no vehicle is detected' and accept the requirement as final.
3. Derive measurable criteria by defining 'empty' as no vehicle detected by the loop sensors for 10 seconds, then state the controller action and timing in the specification.
4. DAsk the users to rewrite the statement themselves because only they know what 'empty' means.

Sample — the full set, with spaced review and mocks, is in the app.

Area 09 · Programming & algorithms

A program has a global variable count initialized to 0 and a function increment() that does not declare its own variable named count; the function only executes count = count + 1. If increment() is called twice, what is the value of the global count after the second call returns?

1. A0
2. B1
3. 2
4. DThe program fails to compile because count is not declared inside increment().

Sample — the full set, with spaced review and mocks, is in the app.