Important MCQs for all competitive exams

In this particular article Important MCQ’s for all competitive exams, We will discuss some most important questions with answers asked in previous years examination.

Part A

Q.1 With forward bias to a pn junction, the width of depletion layer-

(a) Decreases

(b) Increases

(c) Remains the same

(d) None of the above

Answer: Decreases

Q.2 In an intrinsic semiconductor the number of free electrons,.

Important MCQ's for all competitive exams

(a) equal the numbers of holes and electrons

(b) Is greater than the number of the holes

(c) Is less than the number of the holes

(d) None of the above

Answer: equal the numbers of holes and electrons

Q.3 At room temperature, an intrinsic silicon crystal acts approximately as :-

(a) A battery

(b) A conductor

(c) An insulator

(d) A piece of copper wire

Answer: An insulator

Q.4 The barrier field in a p-n junction is directed from … To…

(a) n side to p side

(b) p side to n side

(c) p side to p side

(d) In any direction

Answer: n side to p side

Q.5 Zener diode as a regulator work in …?

(a) Forward bias

(b) Reverse bias

(c) No bias

(d) In any direction

Answer: Reverse bias

Part B

Q.6 The emission from LASER ( light amplification by stimulated emission) of radiation is-

(a) Spontaneous

(b) Stimulated

(c) Thermal

(d) ionic

Answer: Stimulated

Q. 7 A crystal diode is used as…

(a) An amplifier

(b) A rectifier

(c) An oscillator

(d) A voltage regualator

Answer: A rectifier

( A rectifier is a device that converts AC  into DC )

Q.8 An ideal crystal diode is one which behaves as a perfect…when forward biased.

(a) Conductor

(b) Insulator

(c) resistance material

(d) None of the above

Answer: Conductor

Q.9 Which of these is the best description of a zener diode ?

(a) it is a rectifier diode

(b) It is a constant voltage device

(c) It is a constant electric current device

(d) It works in the forward region

Answer: It is a constant voltage device ( this concept is used in regulator)

Q.10 A voltage regulator is a circuit which…?

(a) Converts the AC voltage to DC voltage

(b) smoothed the AC variation in DC output voltage

(c) Maintains constant DC output voltage inspite of the fluctuating AC

(d) None of the above

Answer: Maintains constant DC output voltage inspite of the fluctuating AC

Part C

Q.11 The element that has the biggest size in a transistor is…

(a) Collector

(b) Base

(c) Emitter

(d) Collector- Base- Junction

Answer: Collector

Q.12 The number of depletion layers in a transistor is…

(a) Four

(b) Three

(c) One

(d) two

Answer: Two ( emitter-Base, Base-Collector)

Q.13 A transistor has…

(a) One pn junction

(b) two pn junction

(c) three pn junction

(d) four pn junction

Answer: two pn junction

Q.14 The base of a transistor is…doped

(a) Heavily

(b) Moderately

(c) Lightly

(d) None of the above

Answer: Lightly

Q.15 In a pnp transistor, the majority current carriers are…

(a) Acceptor ions

(b) Donor ions

(c) Free electrons

(d) Holes

Answer: Holes

Part D

Q.16 The Collector of a transistor is…doped?

(a) Heavily

(b) Moderately

(c) Lightly

(d) None of the above

Answer: Moderately

Q.17 A transistor is a… controlled device

(a) Current

(b) Voltage

(c) Both Voltage and current

(d) None of the above

Answer: Current

Q.18 In a transistor… Are the minority carriers-

(a) free electrons

(b) Holes

(c) Donor ions

(d) acceptor ions

Answer: Holes

Q.19 The emitter of a transistor is…doped

(a) Lightly

(b) Heavily

(c) Moderately

(d) None of the above

Answer: Heavily

Q.20 At the base-emitter junctions of a transistor, one finds…

(a) Reverse bias

(b) Wide-depletion layer

(c) Low resistance

(d) None of the above

Answer: Low resistance

(Base-emitter junctions is forward bias in active region of transistor)

 

 

 

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