Labour Officer • 2026 • Paper-III
The primary purpose of the metallic shield in a co-axial cable is
A)
to increase bandwidth capacity
B)
to provide structural support
C)
to protect against electromagnetic interference
D)
to reduce signal attenuation
Correct option C: to protect against electromagnetic interference
Labour Officer • 2026 • Paper-III
In QAM, information is carried in:
A)
Amplitude only
B)
Phase only
C)
Amplitude & phase
D)
Frequency only
Correct option C: Amplitude & phase
Labour Officer • 2026 • Paper-III
The address bus of Intel 8086 is
A)
16-bit
B)
20-bit
C)
8-bit
D)
32-bit
Correct option B: 20-bit
Labour Officer • 2026 • Paper-III
Briefly explain the maximum mode configuration of 8086.
Labour Officer • 2026 • Paper-III
An AM signal has a peak unmodulated carrier voltage Vc = 100 V, a load resistance RL = 50Ω and a modulation index of ma = 1. Determine the carrier power, total sideband power and total power of the modulated AM signal.
Labour Officer • 2026 • Paper-III
The refractive index of the fiber core is
A)
Equal to cladding
B)
Less than cladding
C)
Greater than cladding
D)
Zero
Correct option C: Greater than cladding
Labour Officer • 2026 • Paper-III
In a PCM system, the quantization noise depends upon
A)
The number of quantization levels only
B)
The sampling rate only
C)
Both sampling rate and the number of quantization levels
D)
None of the above
Correct option A: The number of quantization levels only
Labour Officer • 2026 • Paper-III
Interrupts are used to:
A)
Stop CPU permanently
B)
Handle I/O requests
C)
Increase memory
D)
Control cache
Interrupts are signals that temporarily pause the CPU’s current task so it can respond to urgent events, most commonly input/output (I/O) operations from devices like keyboards, disks, or printers. This improves efficiency because the CPU does not have to continuously poll devices.
Why others are wrong:
(a) Stop CPU permanently — interrupts do not stop the CPU permanently; they are temporary.
(c) Increase memory — interrupts have nothing to do with increasing memory.
(d) Control cache — cache management is handled by the memory subsystem, not by interrupts.
Labour Officer • 2026 • Paper-III
Which microprocessor is used in early IBM PCs?
A)
8085
B)
8086
C)
8051
D)
Pentium
The early IBM PCs used the Intel 8088, which is closely related to the 8086 and is commonly grouped with it in basic MCQ discussions. Among the given options, 8086 is the correct microprocessor associated with early IBM PCs. 8085 is an 8-bit microprocessor, 8051 is a microcontroller, and Pentium is a much later processor generation.
Labour Officer • 2026 • Paper-III
A step index fiber has an acceptance angle of 18° in air. The fiber has a relative refractive index of 2.5%. Estimate the value of the critical angle at the core cladding interface of the fiber and also the numerical aperture of the fiber.
Labour Officer • 2026 • Paper-III
The frequency range of Ku band is
A)
4 -8 GHz
B)
8-12 GHz
C)
12-18 GHz
D)
2-4 GHz
Correct option C: 12-18 GHz
Labour Officer • 2026 • Paper-III
If the lower sidebands overlaps the basebands, the distortion is called
A)
Cross-Over distortion
B)
Aliasing
C)
Crosstalk
D)
Distortion
Correct option B: Aliasing
Labour Officer • 2026 • Paper-III
Program counter is used to
A)
store address of the next instruction to be executed
B)
store address of the instruction currently executed
C)
store temporary data to be used in arithmetic operations
D)
store the program of the microprocessor
Correct option A: store address of the next instruction to be executed
Labour Officer • 2026 • Paper-III
In a commercial TV broadcast station, the sound portion of TV signal is frequency modulated with a maximum frequency deviation of 50 kHz and a maximum modulating-signal frequency of 15 kHz. The deviation ratio is
A)
3.3
B)
0.3
C)
750
D)
100
Correct option A: 3.3
Labour Officer • 2026 • Paper-III
What is the difference between INR and INX instruction?
Labour Officer • 2026 • Paper-III
The frequency range for satellite communication is
A)
1 GHz - 30 GHz
B)
10 kHz -100 kHz
C)
1 MHz – 100 MHz
D)
20 MHz – 100 MHz
Correct option A: 1 GHz - 30 GHz
Labour Officer • 2026 • Paper-III
Which of the following is a stack operation?
A)
PUSH
B)
MOVE
C)
LOAD
D)
STORE
A stack operation is an action performed on a stack data structure. PUSH adds an element to the top of the stack, and POP removes an element from the top. Among the given options, PUSH is the stack operation. MOVE, LOAD, and STORE are general data transfer instructions, not stack-specific operations.
Labour Officer • 2026 • Paper-III
The modulation index of an amplitude modulated signal whose maximum amplitude is 10V and minimum amplitude is 5V is
A)
0.65
B)
0.9
C)
0.33
D)
1
Correct option C: 0.33
Labour Officer • 2026 • Paper-III
Calculate the system bandwidth capacity in a FDM system having 200 users with individual bandwidth of 3 MHz.
A)
66.66 MHz
B)
900 MHz
C)
600 MHz
D)
300 MHz
Correct option C: 600 MHz
Labour Officer • 2026 • Paper-III
What is the function of isolators and circulators in microwave circuits?
Labour Officer • 2026 • Paper-III
Which of the following instruction is not valid?
A)
MOV AX, BX
B)
MOV DS, 5000H
C)
MOV AX, 5000H
D)
PUSH AX
Correct option B: MOV DS, 5000H
Labour Officer • 2026 • Paper-III
If modulation index of an AM wave is increased from 1.5 to 2, then the transitted power
A)
remains same
B)
increases by 20%
C)
increases by 41%
D)
increases by 50%
Correct option C: increases by 41%
Labour Officer • 2026 • Paper-III
Horn antenna is used for:
A)
Microwave frequencies
B)
Audio signals
C)
Optical signals
D)
HF signals
Correct option A: Microwave frequencies
Labour Officer • 2026 • Paper-III
A circulator is typically a:
A)
4-port device
B)
2-port device
C)
3-port device
D)
5-port device
Correct option C: 3-port device
Labour Officer • 2026 • Paper-III
In TDM, non-essential frequency components of the modulating signal are removed by
A)
Pre-alias filter
B)
Modulator
C)
Sampler
D)
Attenuator
Correct option A: Pre-alias filter
