1. Determine the eddy current loss (in W) in a material having eddy current coefficient of 1, thickness of 0.02 m and a volume of 1 cubic metre, which is kept in a magnetic field of maximum flux density of 2 T and supplied by a frequency of 50 Hz ?

2

3

5

4

Answer: 4

Explanation:


2. What will be the self-inductance (in mH) of a 4 m long air-core solenoid, if the diameter of the solenoid is 50 cm and has 300 turns ?

5.54

6.94

7.85

8.64

Answer: 5.54

Explanation:


3. What is the coupling factor between the two coils, each having self inductance of 25 mH and the mutual inductance between the two is 25 mH ?

0.5

0.75

1

2

Answer: 1

Explanation:


4. Determine the magnitude of the EMF (in V} induced beMeen the axis of rotation and the rim of the disc, when the disc of radius 10 cm rotates with an angular velocity of 10 revolutions per second, which is placed in a magnetic field of 4 T acting parallel to the rotation of the disc. ?

0.5

0.75

1

1.25

Answer: 1.25

Explanation:


5. Determine the peak value (in A) of the current used by a motor rated at 220 V, 30 A ?

21.2

30

42.4

51.9

Answer: 42.4

Explanation:


6. What will be the frequency (in Hz) of a sinusoidal wave, when the time period is 20 ms ?

50

60

40

30

Answer: 50

Explanation:


7. At resonant frequency, the impedance of a series resonant circuit is ?

zero

maximum

infinite

minimum

Answer: minimum

Explanation:


8. Determine the value of the phase angle (in degrees) in a series RC circuit having a resistance of 20 ohms and capacitive reactance of 11.56 ohms when supplied by a frequency of 50 Hz ?

60

30

90

45

Answer: 30

Explanation:


9. A 3-phase delta connected system is supplied by a line voltage of 200 V. The value of phase current is 30 A. What is the total power consumed (in W) by the system, if the current lags the voltage by 30 degrees ?

16.32

14.45

15.59

16.69

Answer: 15.59

Explanation:


10. Determine the reactive power (in kVAR) of a 3-phase delta connected system having a line voltage of 400 V, line current of 40 A and the phase difference between the voltage and current is 45 degrees ?

14.4

15.8

18.7

19.6

Answer: 19.6

Explanation: