NEET PYQs for Semiconductor Electronics: Materials, Devices and Simple Circuits with Solutions: Practice NEET Previous Year Questions

1.

A full wave rectifier circuit consists of two p-n junction diodes, a centre-tapped transformer, capacitor and a load resistance. Which of these components remove the ac ripple from the rectified output?

• Load resistance
• A centre-tapped tranformer
• p-n juntion diodes
• Capacitor

2.

The increase in the width of the depletion region in a p-n junction diode is due to :

• forward bias only
• reverse bias only
• both forward bias and reverse bias
• increase in forward current

3.

In half wave rectification, if the input frequency is 60 Hz, then the output frequency would be:

• Zero
• 30 Hz
• 60 Hz
• 120 Hz

4.

Consider the following statements (A) and (B) and identify the correct answer. 
(A) A zener diode is connected in reverse bias when used as a voltage regulator. 
(B) The potential barrier of the p-n junction lies between 0.1 V to 0.3 V.

• (A) is incorrect but (B) is correct

• (A) and (B) both are correct

• (A) and (B) both are incorrect

• (A) is correct and (B) is incorrect

5.

For the given circuit, the input digital signals are applied at the terminals A, B and C. What would be the output at the terminal y?

6.

The I-V characteristics shown above are exhibited by a:

• Light emitting diode
• Zener diode
• Photodiode
• Solar cell

7.

For transistor action, which of the following statements is correct ?

• Base, emitter and collector regions should have same doping concentrations.
• Base, emitter and collector regions should have same size.
• Both emitter junction as well as the collector junction are forward biased.
• The base region must be very thin and lightly doped.

8.

The solids which have negative temperature coefficient of resistance are :

• metals
• insulators only
• semiconductors only
• insulators and semiconductors

9.

Given below are two statements:
Statement I: Photovoltaic devices can convert optical radiation into electricity.
Statement II: Zener diode is designed to operate under reverse bias in breakdown region.
In the light of the above statements, choose the most appropriate answer from the options given below:

• Statement I is incorrect but Statement II is correct.

• Statement I and Statement II are incorrect.

• Both Statement I and Statement II are correct.

• Statement I is correct but Statement II is incorrect

10.

The electron concentration in an n-type semiconductor is the same as the hole concentration in a p-type semiconductor. An external field (electric) is applied across each of them. Compare the currents in them

• No current will flow in p-type, current will only flow in n-type

• current in n-type=current in p-type

• current in p-type > current in n-type

• current in n-type > current in p-type

11.

The truth table for the given logic circuit is:

• A B C
  0 0 0
  0 1 1
  1 0 1
  1 1 0
• A B C
  0 0 1
  0 1 0
  1 0 0
  1 1 1
• A B C
  0 0 1
  0 1 0
  1 0 1
  1 1 0
• A B C
  0 0 0
  0 1 1
  1 0 0
  1 1 1

12.

For the logic circuit shown, the truth table is :

13.

For the following logic circuit, the truth table is:

• \(\begin{matrix} A &B  &Y \\   0&0  &0 \\   0&1  &1 \\   1&0  &1 \\   1&1  &1  \end{matrix}\)

• \(\begin{matrix} A &B  &Y \\   0&0  &1 \\   0&1  &0 \\   1&0  &1 \\   1&1  &0  \end{matrix}\)

• \(\begin{matrix} A &B  &Y \\   0&0  &0 \\   0&1  &0 \\   1&0  &0 \\   1&1  &1  \end{matrix}\)

• \(\begin{matrix} A &B  &Y \\   0&0  &1 \\   0&1  &1 \\   1&0  &1 \\   1&1  &0  \end{matrix}\)

14.

In the given circuits (a), (b) and (c), the potential drop across the two p-n junctions are equal in:

• Circuit (a) only
• Circuit (b) only
• Circuit (c) only
• Both circuits (a) and (c)

15.

For a p-type semiconductor, which of the following statements is true ?

• Holes are the majority carriers and pentavalent atoms are the dopants.
• Electrons are the majority carriers and pentavalent atoms are the dopants.
• Electrons are the majority carriers and trivalent atom >re the dopants.
• Holes are the majority carriers and trivalent atoms are the dopants.