250+ TOP MCQs on The P-N Junction as a Diode and Answers

Electronic Devices and Circuits Multiple Choice Questions on “The P-N Junction as a Diode”.

1. How many junction/s do a diode consist?
A. 0
B. 1
C. 2
D. 3
Answer: B
Clarification: Diode is a one junction semiconductor device which has one cathode and anode. The junction is of p-n type.

2. If the positive terminal of the battery is connected to the anode of the diode, then it is known as
A. Forward biased
B. Reverse biased
C. Equilibrium
D. Schottky barrier
Answer: A
Clarification: When a positive terminal is connected to the anode, the diode is forward biased which lets the flow of the current in the circuit.

3. During reverse bias, a small current develops known as
A. Forward current
B. Reverse current
C. Reverse saturation current
D. Active current
Answer: C
Clarification: When the diode is reverse biased, a small current flows between the p-n junction which is of the order of the Pico ampere. This current is known as reverse saturation current.

4. If the voltage of the potential barrier is V₀. A voltage V is applied to the input, at what moment will the barrier disappear?
A. V< V₀
B. V= V₀
C. V> V₀
D. V<< V₀
Answer: B
Clarification: When the voltage will be same that of the potential barrier, the potential barrier disappears resulting in flow of current.

5. During the reverse biased of the diode, the back resistance decrease with the increase of the temperature. Is it true or false?
A. True
B. False
Answer: A
Clarification: Due to the increase in the reverse saturation current due to the increase in the temperature, the back resistance decrease with the increasing temperature.

6. What is the maximum electric field when V_bi=2V , V_R=5V and width of the semiconductor is 7cm?
A. -100V/m
B. -200V/m
C. 100V/m
D. 200V/m
Answer: B
Clarification: Emax=-2(V_bi+V_R)/W
=-2(2+5)/ (7*10^-2)
=-200V/m.

7. When the diode is reverse biased with a voltage of 6V and V_bi=0.63V. Calculate the total potential.
A. 6V
B. 6.63V
C. 5.27V
D. 0.63V
Answer: B
Clarification: Vt=V_bi+V_R
=0.63+6
=6V.

8. It is possible to measure the voltage across the potential barrier through a voltmeter?
A. True
B. False
Answer: B
Clarification: The contacts of the voltmeter have some resistance which will not accurately measure the voltage across the potential barrier. Thus, it is not possible to measure the voltage across the potential barrier.

9. What will be the output of the following circuit? (Assume 0.7V drop across the diode)
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A. 12V
B. 12.7V
C. 11.3V
D. 0V
Answer: C
Clarification: V=12-0.7
=11.3V.

10. Which of the following formula represents the correct formula for width of the depletion region?
A.07/electronic-devices-circuits-questions-answers-pn-junction-diode-q10″>
B. 07/electronic-devices-circuits-questions-answers-pn-junction-diode-q10a”>
C. 07/electronic-devices-circuits-questions-answers-pn-junction-diode-q10b”>
D. 07/electronic-devices-circuits-questions-answers-pn-junction-diode-q10c”>
Answer: A
Clarification: Option a is the correct formula.