Electrical Heating MCQ Question and Answer

Electrical Heating MCQ Question and Answer

1.Which of the following is an advantage of heating by electricity?

  • AQuicker operation
  • BHigher efficiency
  • CAbsence of flue gases 
  • DAll of the above
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Correct Answer : (D)

All of the above

Explanation:

2.Which of the following heating method has maximum power factor?

  • AArc heating
  • BDielectric heating
  • CInduction heating
  • DResistance heating
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Correct Answer : (D)

Resistance heating

Explanation:

The heating method has maximum power factor is Resistance heating.

3.which of the following heating method has leading power factor? 

  • AResistance heating
  • BDielectric heating
  • CArc heating
  • DInduction heating
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Correct Answer : (B)

Dielectric heating

Explanation:

Dielectric heating has leading power factor.

4.which is used for heating non-conducting materials?

  • AEddy current heating
  • BArc heating
  • CInduction heating
  • DDielectric heating
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Correct Answer : (D)

Dielectric heating

Explanation:

Dielectric heating is used for heating non-conducting materials.

5.Which of the following method of heating is not dependent on the frequency of supply?

  • AInduction heating
  • BDielectric heating
  • CElectric resistance heating
  • DAll of the above
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Correct Answer : (C)

Electric resistance heating

Explanation:

Electric resistance heating is not dependent on the frequency of supply.

6.When a body reflects entire radiation incident on it, then it is known as

  • AWhite body
  • BGrey body
  • CBlack body
  • DTransparent body
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Correct Answer : (A)

White body

Explanation:

7.For the transmission of heat from one body to another

  • ATemperature of the two bodies must be different
  • BBoth bodies must be solids
  • CBoth bodies must be in contact
  • DAt least one of the bodies must have some source of heating
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Correct Answer : (A)

Temperature of the two bodies must be different

Explanation:

8.____________ has the highest value of thermal conductivity.

  • ACopper
  • BAluminium
  • CBrass
  • DSteel
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Correct Answer : (A)

Copper

Explanation:

9.Heat transfer by condition will not occur when

  • ABodies are kept in vacuum
  • BBodies are immersed in water
  • CBodies are exposed to thermal radiations
  • DTemperatures of the two bodies are identical
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Correct Answer : (D)

Temperatures of the two bodies are identical

Explanation:

Heat transfer by condition will not occur when Temperatures of the two bodies are identical.

10.A perfect black body is one which

  • ATransmits all incident radiations
  • BAbsorbs all incident radiations
  • CReflects all incident radiations
  • DAbsorbs, Reflects and Transmits all incident radiations
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Correct Answer : (B)

Absorbs all incident radiations

Explanation:

A perfect black body is one which Absorbs all incident radiations.

11.Heat is transferred simultaneously by condition, convection and radiation

  • AInside boiler furnaces
  • BDuring melting of ice
  • CThrough the surface of the insulted pipe carrying steam
  • DFrom refrigerator coils to freezer of a refrigerator
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Correct Answer : (A)

Inside boiler furnaces

Explanation:

Heat is transferred simultaneously by condition, convection and radiation inside boiler furnaces.

12.The process of heat transfer during the re-entry of satellites and missiles, at very high speeds, into earth?s atmosphere is known as

  • AAblation
  • BRadiation
  • CViscous dissipation
  • DIrradiation
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Correct Answer : (A)

Ablation

Explanation:

The process of heat transfer during the re-entry of satellites and missiles, at very high speeds, into earth’s atmosphere is known as Ablation.

13.Which of the following has the highest value of thermal conductivity?

  • AWater
  • BSteam
  • CSolid ice
  • DMelting ice
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Correct Answer : (C)

Solid ice

Explanation:

Solid ice has the highest value of thermal conductivity.

14.Induction heating process is based on which of the following principles?

  • AThermal ion release principle
  • BNucleate heating principle
  • CResistance heating principle
  • DElectro-magnetic induction principle
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Correct Answer : (D)

Electro-magnetic induction principle

Explanation:

Induction heating process is based on Electro-magnetic induction principle.

15.Which of the following insulating materials is suitable for low temperature applications?

  • AAsbestos paper
  • BDiatomaceous earth
  • C80 percent magnesia
  • DCork
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Correct Answer : (B)

Diatomaceous earth

Explanation:

Diatomaceous earth is suitable for low temperature applications.

16.A non-dimensional number generally associated with natural convection heat transfer is

  • APrandtl number
  • BGrashoff number
  • CPecelet number
  • DNusselt number
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Correct Answer : (B)

Grashoff number

Explanation:

A non-dimensional number generally associated with natural convection heat transfer is Grashoff number.

17.The temperature inside a furnace is usually measured by

  • AOptical pyrometer
  • BMercury thermometer
  • CAlcohol thermometer
  • DAny of the above
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Correct Answer : (A)

Optical pyrometer

Explanation:

The temperature inside a furnace is usually measured by Optical pyrometer.

18.Which of the following will happen if the thickness of refractory wall of furnace is increased?

  • AHeat loss through furnace wall will increase
  • BTemperature inside the furnace will fall 
  • CTemperature on the outer surface of furnace walls will drop
  • DEnergy consumption will increase
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Correct Answer : (C)

Temperature on the outer surface of furnace walls will drop

Explanation:

If the thickness of refractory wall of furnace is increased, then the temperature on the outer surface of furnace walls will drop.

19.The material of the heating element for a furnace should have

  • ALower melting point
  • BHigher temperature co-efficient
  • CHigh specific resistance
  • DAll of the above
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Correct Answer : (C)

High specific resistance

Explanation:

The material of the heating element for a furnace should have High specific resistance.

20.In a resistance furnace the atmosphere is  ____________

  • AOxidizing
  • BDeoxidising
  • CReducing
  • DNeutral
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Correct Answer : (A)

Oxidizing

Explanation:

In a resistance furnace the atmosphere is Oxidizing.