61. Dielectric loss is proportional to
(a) frequency.
(b) (frequency)2.
(c) (frequency)3.
(d) (frequency)1/2.
Answer: (a) frequency.
62. The dielectric loss in a dielectric is proportional to
(a) voltage impressed on the dielectric.
(b) the square of the voltage impressed on the dielectric.
(c) the square root of the voltage impressed on the dielectric.
(d) none of the above.
Answer: (b) the square of the voltage impressed on the dielectric.
63. For heating of plywood, the frequency should be
(a) 1 – 2 MHz
(b) 10 – 25 kHz
(c) 1 kHz
(d) 100 Hz
Answer: (a) 1 – 2 MHz
64. The normal voltage used in dielectric heating is
(a) 1.5 kV
(b) 15 kV
(c) 33 kV
(d) 66 kV
Answer: (a) 1.5 kV
65. For dielectric heating, with the increase of mass of workpiece, the optimum frequency for maximum power transfer
(a) increases.
(b) decreases.
(c) independent of mass.
Answer: (b) decreases.
66. For dielectric heating the range of frequency normally employed is
(a) 10 kHz to 100 kHz
(b) 100 kHz to 10 MHz
(c) 1 MHz to 10 MHz
(d) 10 MHz to 40 MHz
Answer: (d) 10 MHz to 40 MHz
67. Furnaces used for cremation are
(a) electric resistance heating.
(b) electric arc heating.
(c) dielectric heating.
(d) high frequency eddy current heating.
Answer: (a) electric resistance heating.
68. In an electric room heat convector the method of heating used is
(a) arc heating.
(b) resistance heating.
(c) induction heating.
(d) infrared heating.
Answer: (b) resistance heating.
69. When the composition of non-ferrous metal is to be varied frequently or when heating is intermittent ………. furnace is desirably used.
(a) direct resistance
(b) direct arc
(c) indirect resistance
(d) Ajax Wyatt
Answer: (c) indirect resistance
70. Hysteresis loss and eddy current loss are used in
(a) resistance heating.
(b) dielectric heating.
(c) induction heating of steel.
(d) induction heating of brass.
Answer: (c) induction heating of steel.
71. The power factor will be leading in ease of
(a) dielectric heating.
(b) induction heating.
(c) electric arc heating.
(d) resistance heating.
Answer: (a) dielectric heating.
72. The method of heating used for non-conducting materials is
(a) induction heating.
(b) dielectric heating.
(c) electric resistance heating.
(d) electric arc heating.
Answer: (b) dielectric heating.
73. The method appropriate for heating of non-ferrous metals is
(a) indirect resistance heating.
(b) radiant heating.
(c) indirect arc heating.
(d) dielectric heating.
Answer: (c) indirect arc heating.
74. The method suitable for heating of conducting medium is
(a) induction heating.
(b) indirect arc heating.
(c) eddy current heating.
(d) radiant heating.
Answer: (a) induction heating.
75. The most modern method for food processing is
(a) induction heating.
(b) resistance heating.
(c) dielectric heating.
(d) eddy current heating.
Answer: (c) dielectric heating.
76. ……….. is not an application of dielectric heating.
(a) Food processing.
(b) Soldering.
(c) Gluing of wood.
(d) Diathermy.
Answer: (b) Soldering.
77. The power factor will be maximum in-case of
(a) electric arc heating.
(c) induction heating.
(b) resistance heating.
(d) dielectric heating.
Answer: (b) resistance heating.
78. The main advantage of dielectric heating is that
(a) it can be used for drying the explosives.
(b) heating occurs in the material itself.
(c) heating occurs due to the high frequency.
(d) none of the above.
Answer: (b) heating occurs in the material itself.
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