Electronics MCQs

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Hall effect is observed in a specimen when it is carrying current and is placed in a magnetic field. The resulting electric field inside the speciment will be in

  • A. direction normal to both current and magnetic field
  • B. the direction of current
  • C. direction antiparallel to magnetic field
  • D. an arbitrary direction depend upon conductivity
  • Correct Answer: Option A

In photoelectric emission the maximum kinetic energy of emitted electron is proportional to

  • A. SQRT f
  • B. f
  • C. f^2
  • D. f^3
  • Correct Answer: Option B

In a photo transistor the photocurrent is

  • A. emitter base junction
  • B. collector base junction
  • C. collector
  • D. either (a) or (b)
  • Correct Answer: Option B

Fermi level in intrinsic semiconductor is at the centre of forbidden energy band.

  • A. True
  • B. False
  • Correct Answer: Option A

A varactor diode is

  • A. reverse biased
  • B. forward biased
  • C. biased to breakdown
  • D. unbiased
  • Correct Answer: Option A

In a triode the potential of grid (with respect to cathode) is usually

  • A. zero
  • B. negative
  • C. positive
  • D. zero or positive
  • Correct Answer: Option B

Consider the following statements. 1 Etching 2 Exposure to UV radiation 3 Stripping 4 Developing After a wafer has been coated with photo resist the correct sequence of these steps in photolithography is

  • A. 2, 4, 3, 1
  • B. 2, 4, 1, 3
  • C. 4, 2, 1, 3
  • D. 3, 2, 3, 1
  • Correct Answer: Option C

In a p-n-p transistor operating in forward active mode

  • A. base is positive with respect to emitter and collector
  • B. base is negative with respect to emitter and collector
  • C. emitter is positive with respect to base and base is positive with respect to collector
  • D. emitter is negative with respect to base and base is positive with respect to collector
  • Correct Answer: Option C

Assertion (A): Field emission is substantially independent of temperature. Reason (R): When a high electric field is created at metal surface field emission may occur.

  • A. Both A and R are true and R is correct explanation of A
  • B. Both A and R are true but R is not a correct explanation of A
  • C. A is true but R is false
  • D. A is false but R is true
  • Correct Answer: Option B

Consider the following circuit configuration 1 common Emitter 2 common Base 3 emitter follower 4 emitter follower using Darlington pair. The correct sequence in increasing order of I/P impedance of these configuration:

  • A. 2, 1, 4, 3
  • B. 1, 2, 4, 3
  • C. 2, 1, 3, 4
  • D. 1, 2, 3, 4
  • Correct Answer: Option B