57. If 'f' be the frequency, then dielectric loss is proportional to

A. f

B. f2

C.

D.

58. For heating of plywood, the frequency should be

A. 100 Hz

B. 1000 Hz

C. 10 - 20 kHz

D. 1 - 2 MHz

59. Quantities having the unit "lux" is

A. Utilization factor

B. Luminous flux

C. Luminous intensity

D. Illumination

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.

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

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

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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