NTA UGC NET/JRF Exam, June -2020 (Electronic Science)

Total Questions: 100

31. In a FDM system, 10 channels are multiplexed. Each channel having a BW of 50 kHz, If the guard band between the channels are 1 kHz, the minimum bandwidth required for transmission is:

Correct Answer: C. 509 kHz

32. The main objective of CELL in a cellular mobile system is:

Correct Answer: C. Frequency re-use

33. In the following circuit β is in the range of 8 to 40. R𝔠 = 11 2, V𝔠𝔠 = 200 V, Vg = 10 V. If the V𝔠ᴇ (saturation) = 1.0 V and Vʙᴇ (sat) = 1.5 V, over drive factor = 5. The value of power loss in the transistor is given by:

Correct Answer: A. 35.07 W

34. A three phase four pole induction motor is operating on an input frequency of 75 Hz and slip of 4%. If the rotor resistance of the machine is 1 2. The torque developed by the motor is given by: (Assume the operating volatge is 415 V, assuming stator voltage drop = 0)

Correct Answer: A. 6889 syn. watts

35. Insertion of negative feedback in control system affects:

Correct Answer: B. the transient response to decay very fast

36. For the following First Order System, The value of steady state error is given by:

Correct Answer: A.

37. A dual-slope integrating type of A/D converter has an integrating capacitor of 0.1 µF and a resistance of 100 kN. If the reference voltage is 2 V, and the output of the integrator is not to exceed to 10 V, the value of maximum time the reference voltage can be integrated is:

Correct Answer: B. 50 m second

38. The velocity transducer consists of a moving coil suspended in the magnetic field of а permanent magnet, It is not used for measurement of velocities developed in а:

Correct Answer: D. discrete manner

39. What is not the source of Error in a Thermocouple transducer?

Correct Answer: D. Hall effect

40. Which is not the important characteristics of thermistors that make them extremely useful in measurement and control applications?

Correct Answer: D. the power - time characteristic