Electronic Devices Chapter-Wise Test 8

Correct answer Carries: 4.

Wrong Answer Carries: -1.

In a half-wave rectifier, the output frequency is:

A half-wave rectifier conducts only during the positive half-cycle of the AC input, so the output frequency remains the same as the input frequency (e.g., 50 Hz input gives 50 Hz output).

Equal to the input frequency
Twice the input frequency
Half the input frequency
Zero
1

The output of a full-wave rectifier without a filter is:

A full-wave rectifier converts both AC half-cycles to DC, producing a pulsating DC output with peaks corresponding to the input waveform, not steady without a filter.

Steady DC
Pulsating DC
Pure AC
Zero voltage
2

The reverse current in a diode increases sharply at:

The reverse current remains small (\( \mu \text{A} \)) until the reverse bias reaches the breakdown voltage (\( V_{br} \)), where it increases sharply due to junction breakdown.

Threshold voltage
Forward bias voltage
Breakdown voltage
Equilibrium voltage
3

A diode in reverse bias primarily allows current due to:

In reverse bias, the small current (\( \mu \text{A} \)) is due to minority carriers (electrons in p-side, holes in n-side) drifting across the junction under the electric field.

Minority carriers
Majority carriers
Ionized impurities
Neutral atoms
1

A p-type semiconductor is doped with:

A p-type semiconductor is created by doping a tetravalent semiconductor (e.g., Si) with a trivalent impurity (e.g., B, Al, In), which accepts electrons and creates holes as majority carriers.

Pentavalent atoms
Trivalent atoms
Tetravalent atoms
Divalent atoms
2

The primary advantage of a semiconductor diode over a vacuum tube is:

Semiconductor diodes are small, low-power, operate at low voltages, and have long life and high reliability compared to bulky, high-power vacuum tubes.

High power consumption
Large size
High operating voltage
Long life and reliability
4

The diffusion current in a p-n junction is due to:

Diffusion current arises from the movement of carriers (holes from p-side to n-side, electrons from n-side to p-side) due to concentration gradients across the junction during its formation.

Concentration gradient
Electric field
Thermal energy
External voltage
1

During p-n junction formation, the depletion region is formed due to:

The depletion region forms due to diffusion of electrons and holes across the junction, leaving behind immobile ionized impurities that create a space-charge region.

Drift of minority carriers
Thermal generation
Diffusion of charge carriers
Recombination of carriers
3

Which of the following is NOT a pentavalent dopant?

Pentavalent dopants (valency 5) include P, As, and Sb. Indium (In) is trivalent (valency 3) and used for p-type doping, not n-type.

Phosphorus (P)
Arsenic (As)
Antimony (Sb)
Indium (In)
4

The diode in a half-wave rectifier conducts during:

In a half-wave rectifier, the diode is forward biased and conducts only during the positive half-cycle of the AC input, blocking the negative half-cycle.

Negative half-cycle
Full cycle
Zero voltage periods
Positive half-cycle
4

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