MCQ on Electronics and Communication

21-Which of the following is a bidirectional device?
(A) Zener diode
(B) SCR
(C) LED
(D) Triac
22-The function of NOT gate is to
(A) Invert an input signal
(B) Add two input signals
(C) Multiply two input signals
(D) Perform as a universal gate
23-Which of the following is the fastest switching device?
(A) MOSFET
(B) JFET
(C) BJT
(D) pentode
24-Henry is the unit of
(A) Capacitance
(B) Power
(C) Inductance
(D) Resistance
25-A dynamic microphone is a ___ type transducer.
(A) Acoustical
(B) Thermal
(C) Optical
(D) Variable resistance
26-The ripple factor of a halfwave rectifier is
(A) 0.482
(B) 0.812
(C) 1.21
(D) 40.6
27-Which of the following is a single input flip-flop?
(A) R-S
(B) D
(C) JK
(D) Clocked RS
28-Antimony is a ___ type of doping material.
(A) trivalent
(B) semiconductor
(C) acceptor
(D) pentavalent
29-IC 7912 is
(A) two input Quad XNOR gate
(B) two input Quad XOR gate
(C) Negative voltage regulator for 12 V
(D) Positive voltage regulator for 12 V
30-Which of the following is an insulator?
(A) Ferrite
(B) Germanium
(C) Silicon
(D) Zinc
ANSWERS:
21-(D), 22-(A), 23-(A), 24-(C), 25-(A), 26-(C), 27-(B), 28-(D), 29-(C), 30-(A)