Electrostatics

41. When 4 volts e.m.f. is applied across a 1 farad capacitor, it will store energy of

2 joules
4 joules
6 joules
8 joules

Detailed SolutionWhen 4 volts e.m.f. is applied across a 1 farad capacitor, it will store energy of

42. Mica capacitors are characterised by all of the following except

stable operation
accurate value
low leakage reactance
low losses

Detailed SolutionMica capacitors are characterised by all of the following except

43. In a cable capacitor, voltage gradient is maximum at the surface of the

earth
conduction
sheath
insulator

Detailed SolutionIn a cable capacitor, voltage gradient is maximum at the surface of the

44. The unit of capacitance is

henry
ohm
farad
farad/m

Detailed SolutionThe unit of capacitance is

45. The time constant of an R-C circuit is defined as the time during which capacitor charging voltage actually rises to . . . . . . . . percent of its . . . . . . . . value.

37, initial
62, initial
62, final
37, final

Detailed SolutionThe time constant of an R-C circuit is defined as the time during which capacitor charging voltage actually rises to . . . . . . . . percent of its . . . . . . . . value.

46. An electrolytic capacitor is generally made to provide

low capacitance
fixed capacitance
variable capacitance
large value of capacitance

Detailed SolutionAn electrolytic capacitor is generally made to provide

47. Which of the following capacitors preferred for high frequency circuits ?

Air capacitor
Electrolytic capacitor
Mica capacitor
none of the above

Detailed SolutionWhich of the following capacitors preferred for high frequency circuits ?

48. If three 15 uF capacitors are connected in series, the net capacitance is

5 uF
30 uF
45 uF
50 uF

Detailed SolutionIf three 15 uF capacitors are connected in series, the net capacitance is

49. Out of the following capacitors of identical rating which one will have the smallest dimensions ?

Aluminium foil capacitor
Mica capacitor
Ceramic capacitor
Paper capacitor

Detailed SolutionOut of the following capacitors of identical rating which one will have the smallest dimensions ?

50. If the sheet of a bakelite is inserted between the plates of an air capacitor, the capacitance will

decrease
increase
remains unchanged
become zero

Detailed SolutionIf the sheet of a bakelite is inserted between the plates of an air capacitor, the capacitance will

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