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4

Which of the following refrigerant has the lowest boiling point?

A. Ammonia

B. Carbon dioxide

C. Sulphur dioxide

D. R-12

Correct Answer :

B. Carbon dioxide


Related Questions

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4

The reduced ambient air cooling system has

A. One cooling turbine and one heat exchanger

B. One cooling turbine and two heat exchangers

C. Two cooling turbines and one heat exchanger

D. Two cooling turbines and two heat exchangers

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4

In a vapour compression cycle, the refrigerant immediately after expansion valve is

A. Liquid

B. Sub-cooled liquid

C. Saturated liquid

D. Wet vapour

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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 ratio of heat extracted in the refrigerator to the work-done on the refrigerant is called

A. Coefficient of performance of refrigeration

B. Coefficient of performance of heat pump

C. Relative coefficient of performance

D. Refrigerating efficiency

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4

Which of the following statement is correct?

A. The human body can lose heat even if its temperature is less than the atmospheric temperature.

B. The increase in air movement increases the evaporation from the human body.

C. The warm air increases the rate of radiation of heat from the human body.

D. Both (A) and (B)

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4

In a bootstrap air evaporative cooling system, the evaporator is provided

A. Between the combustion chamber and the first heat exchanger

B. Between the first heat exchanger and the secondary compressor

C. Between the secondary compressor and the second heat exchanger

D. Between the second heat exchanger and the cooling turbine

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4

The pressure at the inlet of a refrigerant compressor is called

A. Suction pressure

B. Discharge pressure

C. Critical pressure

D. Back pressure

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4

In a flooded evaporator refrigerator, an accumulator at suction of compressor is used to

A. Collect liquid refrigerant and prevent it from going to compressor

B. Detect liquid in vapour

C. Superheat the vapour

D. Collect vapours

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4

Highest pressure encountered in a refrigeration system should be

A. Critical pressure of refrigerant

B. Much below critical pressure

C. Much above critical pressure

D. Near critical pressure

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4

The higher temperature in vapour compression cycle occurs at

A. Receiver

B. Expansion valve

C. Evaporator

D. Compressor discharge

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4

In aqua ammonia and Lithium bromide water absorption refrigeration systems, the refrigerants are respectively

A. Water and water

B. Water and lithium bromide

C. Ammonia and lithium bromide

D. Ammonia and water

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4

The process, generally used in winter air-conditioning to warm and humidity the air, is called

A. Humidification

B. Dehumidification

C. Heating and humidification

D. Cooling and dehumidification

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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

It is desired to condition the outside air from 70% relative humidity and 45° C dry bulb temperature to 50% relative humidity and 25° C dry bulb temperature (room condition). The practical arrangement will be

A. Dehumidification

B. Cooling and humidification

C. Cooling and dehumidification

D. Dehumidification and pure sensible cooling

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4

The formation of frost on cooling coils in a refrigerator

A. Increases heat transfer

B. Improves C.O.P. of the system

C. Increases power consumption

D. Reduces power consumption

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4

In a refrigeration system, heat absorbed in comparison to heat rejected is

A. More

B. Less

C. Same

D. More for small capacity and less for high capacity

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4

A refrigerating system operating on reversed Brayton refrigeration cycle is used for maintaining 250 K. If the temperature at the end of constant pressure cooling is 300K and rise in the temperature of air in the refrigerator is 50 K, then the net work of compression will be (assume air as working substance with Cp = 1 kJ/kg)

A. 25 kJ/kg

B. 50 kJ/kg

C. 100 kJ/kg

D. 125 kJ/kg

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4

An Electrolux refrigerator is called a __________ absorption system.

A. Single fluid

B. Two fluids

C. Three fluids

D. None of these

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4

The refrigerant used in small tonnage commercial machines (hermetically sealed units) is

A. Ammonia

B. Carbon dioxide

C. Sulphur dioxide

D. R-12

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4

Which of the following refrigerant has the maximum ozone depletion potential in the stratosphere?

A. Ammonia

B. Carbon dioxide

C. Sulphur dioxide

D. Fluorine

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4

The general rule for rating refrigeration systems (excepting for CO₂ system) is to approximate following h.p. per ton of refrigeration

A. 0.1 to 0.5 h.p. per ton of refrigeration

B. 0.5 to 0.8 h.p. per ton of refrigeration

C. 1 to 2 h.p. per ton of refrigeration

D. 2 to 5 h.p. per ton of refrigeration

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4

In which of the following refrigeration system, waste heat can be effectively used?

A. Vapour compression cycle

B. Vapour absorption cycle

C. Air refrigeration cycle

D. None of these

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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

In vapour compression refrigeration system, refrigerant occurs as liquid between

A. Condenser and expansion valve

B. Compressor and evaporator

C. Expansion valve and evaporator

D. Compressor and condenser

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4

Critical pressure of a liquid is the pressure

A. Above which liquid will remain liquid

B. Above which liquid becomes gas

C. Above which liquid becomes vapour

D. Above which liquid becomes solid

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4

The colour of the flame of halide torch, in case of leakage of Freon refrigerant, will change to

A. Bright green

B. Yellow

C. Red

D. Orange

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The lowest temperature during the cycle in a vapour compression system occurs after

A. Compression

B. Expansion

C. Condensation

D. Evaporation

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A thermostatic expansion valve in a refrigeration system

A. Ensures the evaporator completely filled with refrigerant of the load

B. Is suitable only for constant load systems

C. Maintains different temperatures in evaporator in proportion to load

D. None of the above

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4

During cooling and dehumidification, dry bulb temperature

A. Remains constant

B. Increases

C. Decreases

D. None of these

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4

The process of under-cooling is generally brought about by

A. Circulating more quantity of cooling water through the condenser

B. Using water colder than the main circulating water

C. Employing a heat exchanger

D. Any one of the above