A multiplexer (MUX) (A) is a parallel to serial converter
(B) is also known as data distributor
(C) can be used as a logic function generator
(D) switch the data from several lines to one line
Choose the correct answer from the options given below:
1
(A), (B), (C) and (D)
2
(A), (B) and (D) only
3
(B), (C) and (D) only
4
(A), (C) and (D) only
Official Solution
Correct Option: (1)
A multiplexer (MUX) is a digital switch that can perform various functions:
- Parallel to serial conversion: It converts multiple parallel data inputs to a single serial data output.
- Data distributor: It can distribute one of several inputs to the output based on selection.
- Logic function generator: It can be configured to perform different logic operations by appropriately setting its selection lines.
- Switching data: It switches data from multiple lines to a single output line. Thus, all options (A), (B), (C), and (D) are correct. Final Answer:
02
PYQ 2025
medium
nanoelectronicsID: cuet-pg-
Choose the correct statement from the options below:
1
Non-linear distortion is expected to be minimum in Single Side-band Suppressed Carrier (SSB-SC) systems and Amplitude Modulation (AM).
2
The AM system has a suppressed carrier system, which is cheaper than the performance point of view.
3
The receiver of a suppressed carrier system is simpler and cheaper than that of the AM system.
4
The AM system is always easier to analyze and more efficient.
Official Solution
Correct Option: (3)
Step 1: Understand the receiver design. In an Amplitude Modulation (AM) system, the carrier signal is transmitted along with the modulated signal, requiring more complex receivers. On the other hand, a suppressed carrier system in Single Sideband (SSB) modulation omits the carrier, simplifying the receiver design and reducing the cost.
Step 2: Analyze the correct statement. Thus, the receiver of a suppressed carrier system is simpler and cheaper than that of the AM system. Final Answer:
03
PYQ 2025
medium
nanoelectronicsID: cuet-pg-
The voltage across the inductor for in the given circuit is:
1
2
3
4
Official Solution
Correct Option: (2)
Step 1: Understand the behavior of an inductor. In an RL circuit, the voltage across the inductor for is governed by the natural response of the inductor, given by the equation: where is the time constant. Step 2: Apply the given values. Here, , and we find that the voltage across the inductor for is: Final Answer:
04
PYQ 2026
medium
nanoelectronicsID: cuet-pg-
In optical fibers, does the core or the cladding have a higher refractive index?
1
Core
2
Cladding
3
Both are equal
4
It varies randomly
Official Solution
Correct Option: (1)
Concept:
An optical fiber is a flexible transparent fiber used to transmit light signals over long distances using the principle of total internal reflection. Step 1:Structure of optical fiber.
An optical fiber consists of three main parts:
Core
Cladding
Protective coating
Step 2:Refractive index relationship.
For total internal reflection to occur, the refractive index of the core must be slightly higher than that of the cladding. Step 3:Propagation of light.
Because of this difference in refractive index, light entering the core reflects internally at the core–cladding boundary and travels through the fiber with minimal loss. Conclusion:
Therefore, in optical fibers the core has a higher refractive index than the cladding.
05
PYQ 2026
medium
nanoelectronicsID: cuet-pg-
For an ideal op-amp, what is the output voltage if the feedback resistance is equal to the input resistance in an inverting configuration?
1
2
3
4
Official Solution
Correct Option: (2)
Concept:
In an inverting amplifier configuration of an operational amplifier (op-amp), the input signal is applied to the inverting terminal through an input resistance , while a feedback resistor connects the output to the inverting input. The gain of an ideal inverting amplifier is given by: Step 1:Applying the gain formula.
If the feedback resistance equals the input resistance: then the voltage gain becomes: Step 2:Determining output voltage.
Since the gain is , the output voltage is the negative of the input voltage: Conclusion:
Therefore, when , the output voltage of an ideal inverting op-amp is }.
06
PYQ 2026
medium
nanoelectronicsID: cuet-pg-
In a BJT, what is the primary consequence of the Early effect on the effective base width?
1
The base width increases
2
The base width decreases
3
The base width remains constant
4
The base width becomes zero
Official Solution
Correct Option: (2)
Concept:
The Early effect (also known as base-width modulation) occurs in a Bipolar Junction Transistor (BJT) when the collector-base junction voltage increases. Step 1:Reverse bias of collector-base junction.
In normal transistor operation, the collector-base junction is reverse biased. Increasing this reverse bias causes the depletion region at the collector-base junction to widen. Step 2:Effect on the base region.
As the depletion region expands into the base region, the effective width of the base decreases. Step 3:Impact on transistor current.
A thinner base region allows more charge carriers to pass from emitter to collector, increasing the collector current slightly even if the base current remains constant. Conclusion:
Therefore, the primary consequence of the Early effect is that the effective base width decreases.
