57. If 'f' be the frequency, then dielectric loss is proportional to
A. f
B. f2
C.
D.

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58. For heating of plywood, the frequency should be
A. 100 Hz
B. 1000 Hz
C. 10 - 20 kHz
D. 1 - 2 MHz

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59. Quantities having the unit "lux" is
A. Utilization factor
B. Luminous flux
C. Luminous intensity
D. Illumination

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60. The highest illumination is required
A. for office work
B. for mounting of wrist watches
C. for sorting work in the stores
D. for painting won.

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61. A water boiler at home is switched on to the a.c. mains supplying power at 230 V/ 50 Hz. The frequency of instantaneous power consumed by the boiler is
A. 0 Hz
B. 50 Hz
C. 100 Hz
D. 150 Hz

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62. If v, w, q stand for voltage, energy and charge, then v can be expressed as
A. v =dwdq
B. v =dw
C. dv =dq
D. dv = ?dw

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63. The voltages at the two ends of a line are 132 kV and its reactance is 40 ohms. The capacity of the line is :
A. 435.6 MW
B. 217.5 MW
C. 251.5 MW
D. 500 MW

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