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

Total Questions: 100

41. dV/dt protection is provided to thyristor circuit by using:

Correct Answer: D. snubber circuits

42. For constant load and supply voltage, two DC series motors will develop maximum torque when both are connected in

Correct Answer: B. parallel

43. At certain loading condition, back e.m.f. in DC motor was found half of the supply voltage. Then power delivered by DC motor is:

Correct Answer: B. maximum

44. An SCR is connected across 200 V battery through 0.2 H inductance. If the latching current in the eircuit is 3 mA, what is the minimum width of the gating pulse required to properly turn on the SCR?

Correct Answer: C. 3 µS

45. In forward blocking region of SCR which of the following statements is correct?

Correct Answer: B. Outer junctions J₁ and J₃ are in forward biased while J₂ is in reversed biased

46. A capacitance transducer can be used for the measurement of:

Correct Answer: D. All of the above

47. A platinum RTD has a resistance of 100 ohm at °C. If temperature coefficient is 0.004/°C, what would be the change in resistance if temperature rise is 50°C?

Correct Answer: C. 20 Ω

48. There is a spectrum analyzer with a thirdorder intercept point of +30 dB and noise level of -95 dB. Dynamic range of the spectrum analyzer is approximately

Correct Answer: A. 83 dB

49. A sinusoidal voltage is measured by CRO. Vertical distance between the positive and negative peaks is 8 cm. If the scale of the CRO is set at 5 mV/cm, then peak value of voltage will be:

Correct Answer: A. 20 mV

50. In a Schering bridge, dial of variable capacitor is calibrated directly in terms of dissipation factor of unknown arm. At 50 Hz frequency the value of dissipation factor of unknown capacitor was found to be D. What would be the value of dissipation factor at 60 Hz?

Correct Answer: D.