61. The induced e.m.f. in a coil of 0.8 mH carrying 2A current and reversed in 0.4 seconds is

- 0.16 V
- 0.4 V
- 0.008 V
- 0.064 V

62. A coil of 150 turns is linked with a flux of 10 mWb when carrying a current of 10 A. The inductance of the coil is

- 1.5 H
- 15 H
- 0.15 H
- 15 mH

63. Inductance is the property to

- oppose the change in resistance
- oppose the change in frequency
- oppose the change in current
- oppose the change in voltage

64. Two coils with self-inductance 1 H and 2 H having a mutual inductance of 1 H between them carry currents of 2 A and respectively. The total energy stored in the field, in joules, is

65. A 8 H choke is carrying a current of 500 mA. The energy supplied by inductor is

- 2 J
- 4 J
- 0.5 J
- 1 J

66. If λ is the flux linkage of a coil and I is the current through the coil then inductance of the coil is

- L = i
^{2}λ - L = i/λ
- L = λ/i
- L = iλ

67. Linkage flux per unit current is called

- capacitance
- resistance
- inductance
- capacitive reactance

68. Is it possible to prevent by very fast operation of the switch the switching spark produce during switching off of an inductance?

- No, the faster the circuit is opened, the higher is the self-induced voltage.
- Yes, as long as the circuit is opened fast enough
- Yes, as long as the switch can withstand the high switching speed
- Yes, if the current is less than 50 A

69. Two coupled coils of L_{1} = 0.8 H and L_{2} = 0.2 H have a coupling coefficient k = 0.9. The mutual inductance M is

- 0.144 H
- 0.23 H
- 0.36 H
- 0.43 H

70. The classical analogous of a simple lever is

- capacitor bridge
- transformer
- mutual inductor
- none of these

71. Henry is the unit of measurement for which of the following properties?

- reactance
- capacitance
- resistance
- induction

72. The current passing through an inductor is 4A. The energy stored in the inductor of inductance 0.2 henry will be

- 0.8 J
- 8 J
- 1.6 J
- 0.16 J

73. An inductor stores energy in what form?

- electrostatic field
- electromagnetic field
- magnetic field
- core