The formation of frost on cooling coils in a refrigerator

Formation of frost on evaporator in refrigerator

A

Results in loss of heat due to poor heat transfer

B

Increases heat transfer rate

C

Is immaterial

D

Can be avoided by proper design

One fourth the price of a TV is equal to 1/6th the price of a refrigerator. If the total cost of the TV and the refrigerator is Tk 60000, what is the price of the TV?

A

Tk 22000

B

Tk 24000

C

Tk 27500

D

None of these

Often before sunrise on a clear, calm, cold morning, ice (frost) can be seen on the tops of parked cars, even when the air temperature is above freezing. This condition happens because the tops of the cars are cooling by:

A

Conduction

B

Convection

C

Latent heat

D

Radiation

Frost formation on the evaporator tubes in the domestic refrigerators

A

Can be prevented by proper design

B

Decreased compressor power

C

Causes heat loss due to poor heat transfer

D

Is immaterial

In a refrigerator what produces the cooling ?

A

The ice which deposits on the freezer

B

The sudden expansion of a compressed gas

C

The evaporation of a volatile liquid

D

None of these

________ cooling is the process of dissipating the armature and field winding losses to a cooling medium circulating within the winding insulation wall

A

Direct

B

Indirect

C

Conventional

D

Any of the above

The cooling effect in a cooling tower can not be increased by

A

Increasing the air velocity over the wet surfaces

B

Reducing the humidity of entering air

C

Lowering the barometric pressure

D

None of these

Gas cooling as compared to water cooling of nuclear reactors

A

Can not attain a high temperature

B

Is more efficient as gas has a higher specific heat

C

Can produce only saturated steam for feeding to power turbine

D

None of these

The ratio of the temperature rise of cooling water to the vacuum temperature minus inlet cooling water temperature is called

A

Condenser efficiency

B

Vacuum efficiency

C

Nozzle efficiency

D

Boiler efficiency

Transformers with a capacity of up to _____ have a cooling radiator system with natural cooling

A

2 MVA

B

5 MVA

C

7.5 MVA

D

10 MVA

The formation of frost on cooling coils in a refrigerator

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