NTA UGC NET/JRF Exam, December-2019 (Electronic Science)

51. Which of the following semi conductor devices are hetero structure devices?

(a) HEMТ
(b) MODFET
(c) UJT
(d) GUNN Diode
The options are:

A. (a) and (b) are correct
B. (a) and (c) are correct
C. (c) and (d) are correct
D. (b) and (d) are correct

Correct Answer: A. (a) and (b) are correct

52. The voltage gain of a common source amplifier shown in following figure is:

Options:

A. (a) and (c) are correct
B. (b) and (d) are correct
C. (a) is correct, but (d) is wrong
D. (c) and (d) are correct

Correct Answer: C. (a) is correct, but (d) is wrong

53. Total energy of an absorbed photon in eV is:

Options are:

A. (a) and (b) are correct
B. (a) is correct, but (c) is wrong
C. (c) is correct, but (d) is wrong
D. (d) is correct, but (a) is wrong

Correct Answer: B. (a) is correct, but (c) is wrong

54. In MOS technology, the isolation used is:

(a) diode isolation
(b) P-N Junction isolation
(c) Oxide isolation
(d) Vacuum isolation
Options are:

A. (a) and (c) are correct
B. (b) is correct, but (c) is wrong
C. (c) is correct, but (a) is wrong
D. (b) and (d) are correct

Correct Answer: C. (c) is correct, but (a) is wrong

55. Read the following statements regarding z-transform

(a) The ROC is a ring or disk in the z-plane centred at the origin
(b) The ROC contains all poles
(c) If x(n) is a finite duration sequence, then the ROC is the entire z-plane except possibly z = 0 or z =
(d) If x(n) is a right-sided sequence, ROC extends inward from the innermost nonzero poles in x(z) to z = 0
Which of the above statements are correct?

A. (a) and (b)
B. (b) and (c)
C. (a) and (d)
D. (a) and (c)

Correct Answer: D. (a) and (c)

56. Consider the following statements regarding the complete incidence matrix (A) of order n x b:

(a) The element aᵢⱼ of A = 1, if branch j is associated with node i and orientation is towards node i
(b) The element aᵢⱼ of A = -1, if the branch, j is the cut set i and the orientation coincide
(c) The element aᵢⱼ of A = 1, if the branch j is associated with node i and orientation is away from node i
(d) The element aᵢⱼ of A = 0, if the branch j is not associated with node i Which of the above statements are correct?

A. (a) and (b)
B. (b) and (c)
C. (c) and (d)
D. (d) and (a)

Correct Answer: C. (c) and (d)

57. Consider the following statements:

(a) BJT is a current-controlled device with high input impedance and high gain band width
(b) FET is a voltage-controlled device with high input impedance and low gain bandwidth
(c) UJT is a negative resistance device and can be used as an oscillator
(d) FET and UJT can be used for amplification
Which of the above statements are correct?

A. (a) and (b)
B. (b) and (c)
C. (c) and (d)
D. (a) and (d)

Correct Answer: B. (b) and (c)

58. For an instrumentation amplifier, the following parameters are given:

(a) high input resistance and low power consumption
(b) low input resistance and low power consumption
(c) high CMRR and high slew rate
(d) high CMRR and low slew rate
Which of the following option correctly depicts performance parameters of an instrumentation amplifier?

A. (b) and (d) are correct
B. (a) and (d) are correct
C. (a) and (c) are correct
D. (b) and (c) are correct

Correct Answer: C. (a) and (c) are correct

59. Consider the following statements about Schmitt Trigger:

(a) The output of a Schmitt Trigger is a square wave when input is a sine wave
(b) Schmitt Trigger can be. used in Triangular wave and saw tooth wave generators
(c) The comparator with negative feedback is said to exhibit hysteresis, a dead band condition
(d) The output is impulse waveform when the input to Schmitt Trigger is saw tooth wave
Which of the above statements are correct?