JEE Physics Semiconductor Electronics MCQs Set C

Question. If a full wave rectifier circuit is operating from 50 Hz mains, the fundamental frequency in the ripple will be
(a) 100 Hz
(b) 70.7 Hz
(c) 50 Hz
(d) 25 Hz

Answer: A

Question. Which of the following statement is False?
(a) Majority carries in a n-type semiconductors are holes
(b) Pure Si doped with trival ent impurities gives a p-type semiconductor
(c) Minority carries in a p-type semiconductor are electrons
(d) The resistance of intrinisic semiconductor decreases with increase of temperature

Answer: A

Question. When NPN transistor is used as an amplifier, then
(a) Electrons move from emitter to base
(b) Holes move from collector to base
(c) Electrons move from collector to base
(d) Holes move from base to collector

Answer: A

Question. The voltage gain of an amplifier with 9% negative feedback is 10. The voltage gain without feedback will be
(a) 100
(b) 10
(c) 90
(d) 1.25

Answer: A

Question. An oscillator is nothing but an amplifier with
(a) Positive feedback
(b) Negative feedback
(c) Voltage gain
(d) No feedback

Answer: A

Question. A n-p-n transistor conducts in active mode when
(a) Collector is positive and emitter is negative with respect to the base
(b) Both collector and emitter are positive with respect to the base
(c) Collector is positive and emitter is at same potential as the base
(d) Both collector and emitter are negative with respect to the base

Answer: A

Question. The device that can act as a complete electronic circuit is
(a) Integrated circuit
(b) Junction transistor
(c) Junction diode
(d) Zener diode

Answer: A

Question. For transistor action
(a) Base, emitter and collector regions should have similar size and doping concentrations.
(b) The base region must be very thin and lightly doped.
(c) The emitter-base junction is forward biased and base-collector junction is reverse biased.
(d) Both the emitter-base junction as well as the base collector junction are forward biased.
Which one of the following pairs of statements is correct?
(a) (b), (c)
(b) (c), (d)
(c) (a), (b)
(d) (a), (d)

Answer: A

Question. In an n-p-n transistor working in active mode, the depletion region
(a) At emitter-base junction is thinner than that at collector-base junction
(b) At emitter-base junction is wider than that at collector-base junction
(c) Is not formed
(d) At the two junctions have equals width

Answer: A

Question. Which of the conditions must be satisfied to operate a transistor amplifier?
(a) Emitter-base is forward biased junctions collector-base is reverse biased
(b) Emitter-base and collector-base junctions are forward biased
(c) Emitter-base is reverse biased collector-base is forward biased
(d) Emitter-base and collector-base junctions both are reverse biased

Answer: A

Question. The barrier potential of a p-n junction depends on :
a. Type of semiconductor material
b. Amount of doping
c. Temperature
Which one of the following is correct?
(a) a, b and c
(b) b only
(c) b and c only
(d) a and b only

Answer: A