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1) By the use of which of the following, high frequency power supply for induction furnaces can be obtained ? a. Coreless transformers b. Current transformers c. Motor-generator set d. Multi-phase transformer
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2) The temperature inside a furnace is usually measured by which of the following ? a. Optical pyrometer b. Mercury thermometer c. Alcohol thermometer d. Any of the above
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3) Which of the following insulating materials was suitable for low temperature applications ? a. Asbestos paper b. Diatomaceous earth c. 80 percent magnesia d. Cork
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4) The material of the heating element for a furnace should have___________? a. lower melting point b. higher temperature coefficient c. high specific resistance d. all of the above
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5) In an electric room heat convector the method of heating used is______________? a. arc heating b. resistance heating c. induction heating d. dielectric heating
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6) Induction furnaces are employed for which of the following ? a. Heat treatment of castings b. Heating of insulators c. Melting aluminium d. None of the above
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7) Which of the following will happen if the thickness of refractory wall of furnace is increased ? a. Heat loss through furnace wall will increase b. Temperature inside the furnace will fall c. Temperature on the outer surface of furnace walls will drop d. Energy consumption will increase
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8) A non-dimensional number generally associated with natural convection heat transfer is____________? a. Prandtl number b. Grashoff number c. Pecelet number d. Nusselt number
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9) Induction heating process is based on which of the following principles ? a. Thermal ion release principle b. Nucleate heating principle c. Resistance heating principle d. Electro-magnetic induction princi¬ple
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10) The process of heat transfer during the reentry of satellites and missiles, at very high speeds, into earth’s atmosphere is known as_______________? a. ablation b. radiation c. viscous dissipation d. irradiation
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