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What is the correct answer?

4

A refrigerant with the highest critical pressure is

A. R-11

B. R-12

C. R-22

D. Ammonia

Correct Answer :

D. Ammonia


Related Questions

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4

In a refrigeration system, the expansion device is connected between the

A. Compressor and condenser

B. Condenser and receiver

C. Receiver and evaporator

D. Evaporator and compressor

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4

Carbon dioxide is

A. Colourless

B. Odourless

C. Non-flammable

D. All of these

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4

Most of the domestic refrigerators work on the following refrigeration system

A. Vapour compression

B. Vapour absorption

C. Carnot cycle

D. Electrolux refrigerator

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4

In vapour compression cycle the condition of refrigerant is superheated vapour

A. After passing through the condenser

B. Before passing through the condenser

C. After passing through the expansion or throttle valve

D. Before entering the expansion valve

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4

In a vapour compression system, the condition of refrigerant is dry saturated vapour

A. Before entering the compressor

B. After leaving the compressor

C. Before entering the condenser

D. After leaving the condenser

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4

The process, generally used in summer air conditioning to cool and dehumidify the air, is called

A. Humidification

B. Dehumidification

C. Heating and humidification

D. Cooling and dehumidification

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4

Absorption system normally uses the following refrigerant

A. Freon-11

B. Freon-22

C. CO2

D. Ammonia

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4

The ratio of actual mass of water vapour in a given volume of moist air to the mass of water vapour in the same volume of saturated air at the same temperature and pressure, is called

A. Humidity ratio

B. Relative humidity

C. Absolute humidity

D. Degree of saturation

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4

In vapour compression cycle, the condition of refrigerant is very wet vapour

A. After passing through the condenser

B. Before passing through the condenser

C. After passing through the expansion or throttle valve

D. Before entering the compressor

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4

The wet bulb depression indicates _________ humidity of the air.

A. Absolute

B. Relative

C. Specific

D. None of these

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4

In a vapour compression system, the condition of refrigerant before entering the expansion or throttle valve is

A. High pressure saturated liquid

B. Wet vapour

C. Very wet vapour

D. Dry vapour

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4

The fluids used in Electrolux refrigerator are

A. Water and hydrogen

B. Ammonia and hydrogen

C. Ammonia, water and hydrogen

D. None of these

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4

The C.O.P of a refrigeration cycle with increase in evaporator temperature, keeping condenser temperature constant, will

A. Increase

B. Decrease

C. Remain unaffected

D. May increase or decrease depending on the type of refrigerant used

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4

The vapour compression refrigerator employs the following cycle

A. Rankine

B. Carnot

C. Reversed Rankine

D. Reversed Carnot

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4

The central air conditioning system has ________ overall efficiency as compared to individual systems.

A. Same

B. Lower

C. Higher

D. None of these

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4

The emissivity of a polished silver body is __________ as compared to black body.

A. Same

B. Low

C. Very low

D. High

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4

The C.O.P. of a refrigeration cycle with lowering of condenser temperature, keeping the evaporator temperature constant, will

A. Increase

B. Decrease

C. May increase or decrease depending on the type of refrigerant used

D. Remain unaffected

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4

Environmental protection agencies advice against the use of chlorofluorocarbon refrigerants since

A. These react with water vapour and cause acid rain

B. These react with plants and cause greenhouse effect

C. These react with oxygen and cause its depletion

D. These react with ozone layer

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4

If a heat pump cycle operates between the condenser temperature of +27°C and evaporator temperature of -23°C, then the Carnot COP will be

A. 0.2

B. 1.2

C. 5

D. 6

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4

The specific humidity during heating and humidification process.

A. Remains constant

B. Increases

C. Decreases

D. None of these

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4

Choose the wrong statement

A. Temperature of medium being cooled must be below that of the evaporator

B. Refrigerant leaves the condenser as liquid

C. All solar thermally operated absorption systems are capable only of intermittent operation

D. Frost on evaporator reduces heat transfer

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4

Pick up the correct statement about giving up of heat from one medium to other in ammonia absorption system

A. Strong solution to weak solution

B. Weak solution to strong solution

C. Strong solution to ammonia vapour

D. Ammonia vapours to weak solution

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4

The refrigeration effect in a dry evaporator compared to flooded evaporator in a similar plant is

A. Same

B. More

C. Less

D. More or less depending on ambient conditions

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4

The evaporator used in household refrigerators is

A. Frosting evaporator

B. Non-frosting evaporator

C. Defrosting evaporator

D. None of these

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4

In order to collect liquid refrigerant and to prevent it from going to a ________, a device known as accumulator is used at the suction of compressor.

A. Compressor

B. Condenser

C. Expansion valve

D. Evaporator

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4

The C.O.P. of an absorption type refrigerator is given by (where T₁ = Temperature at which the working substance receives heat, T₂ = Temperature of cooling water, and T₃ = Evaporator temperature)

A. [T₁ (T₂ - T₃)] / [T₃ (T₁ - T₂)]

B. [T₃ (T₁ - T₂)]/ [T₁ (T₂ - T₃)]

C. [T₁ (T₁ - T₂)] / [T₃ (T₂ - T₃)]

D. [T₃ (T₂ - T₃)] / [T₁ (T₁ - T₂)]

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4

The suction pipe diameter of refrigerating unit compressor in comparison to delivery side is

A. Bigger

B. Smaller

C. Equal

D. Smaller/bigger depending on capacity

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4

The wet bulb temperature during sensible heating of air

A. Remains constant

B. Increases

C. Decreases

D. None of these

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4

The mass of water vapour present in __________ is called absolute humidity.

A. 1 m3 of water

B. 1 m3 of dry air

C. 1 kg of wet air

D. 1 kg of dry air

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4

Which of the following refrigerants has lowest freezing point?

A. Freon-12

B. NH3

C. CO2

D. Freon-22