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4

The condition of refrigerant as it leaves the compressor in a vapour compression system is

A. Saturated liquid

B. Wet vapour

C. Dry saturated vapour

D. Superheated vapour

Correct Answer :

D. Superheated vapour


Related Questions

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4

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

A mixture of dry air and water vapour, when the air has diffused the maximum amount of water vapour into it, is called

A. Dry air

B. Moist air

C. Saturated air

D. Specific humidity

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4

Critical temperature is the temperature above which

A. A gas will never liquefy

B. A gas will immediately liquefy

C. Water will evaporate

D. Water will never evaporate

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4

An important characteristic of absorption system of refrigeration is

A. Noisy operation

B. Quiet operation

C. Cooling below 0°C

D. Very little power consumption

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4

In a lithium bromide absorption refrigeration system

A. Lithium bromide is used as a refrigerant and water as an absorbent

B. Water is used as a refrigerant and lithium bromide as an absorbent

C. Ammonia is used as a refrigerant and lithium bromide as an absorbent

D. None of the above

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4

Air refrigeration cycle is used in

A. Commercial refrigerators

B. Domestic refrigerators

C. Air-conditioning

D. Gas liquefaction

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4

Degree of saturation or percentage humidity is

A. The mass of water vapour present in 1 m³ of dry air

B. The mass of water vapour present in 1 kg of dry air

C. The ratio of the actual mass of water vapour in a unit mass of dry air to the mass of water vapour in the same mass of dry air when it is saturated at the same temperature and pressure.

D. 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

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4

The temperature of air recorded by a thermometer, when its bulb is surrounded by a wet cloth exposed to the air, is called

A. Wet bulb temperature

B. Dry bulb temperature

C. Dew point temperature

D. None of these

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4

When the air is passed through an insulated chamber having sprays of water maintained at a temperature higher than the dew point temperature of entering air but lower than its dry bulb temperature, then the air is said to be

A. Cooled and humidified

B. Cooled and dehumidified

C. Heated and humidified

D. Heated and dehumidified

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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

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4

Ammonia absorption refrigeration cycle requires

A. Very little work input

B. Maximum work input

C. Nearly same work input as for vapour compression cycle

D. Zero work input

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4

The curved lines on a psychrometric chart indicates

A. Dry bulb temperature

B. Wet bulb temperature

C. Dew point temperature

D. Relative humidity

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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

The coefficient of performance (C.O.P.) of a refrigerator working as a heat pump is given by

A. (C.O.P.)P = (C.O.P.)R + 2

B. (C.O.P.)P = (C.O.P.)R + 1

C. (C.O.P)P = (C.O.P)R - 1

D. (C.O.P)P = (C.O.P)R

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4

The total pressure exerted by the mixture of air and water vapour is equal to the sum of pressures which each constituent would exert, if it occupied the same space by itself. This statement is called

A. Kinetic theory of gases

B. Newton's law of gases

C. Dalton's law of partial pressures

D. Avogadro's hypothesis

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4

The thermostatic expansion valve is used in __________ type of evaporators.

A. Flooded

B. DX coil

C. Dry

D. None of these

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4

The freezing point of R-12 is

A. -86.6°C

B. -95.2°C

C. -107.7°C

D. -135.8°C

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4

In aqua ammonia absorption refrigeration system, incomplete rectification leads to accumulation of water in

A. Condenser

B. Evaporator

C. Absorber

D. None of these

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4

For evaporators and condensers, for the given conditions, the logarithmic mean temperature difference (tm) for parallel flow is ________ that for counter flow.

A. Equal to

B. Less than

C. Greater than

D. None of these

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4

In a domestic vapour compression refrigerator, the refrigerant commonly used is

A. CO₂

B. Ammonia

C. R-12

D. All of these

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4

Efficiency of a Carnot engine is given as 80%. If the cycle direction be reversed, what will be the value of COP of reversed Carnot Cycle?

A. 1.25

B. 0.8

C. 0.5

D. 0.25

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4

The sub-cooling in a refrigeration cycle

A. Does not alter C.O.P.

B. Increases C.O.P.

C. Decreases C.O.P.

D. None of these

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4

Nusselt number (NN) is given by

A. NN = hl/k

B. NN = μ cp/k

C. NN = ρ V l /μ

D. NN = V²/t.cp

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4

A refrigeration system

A. Removes heat from a low temperature body and delivers it to a high temperature body

B. Removes heat from a high temperature body and delivers it to a low temperature body

C. Rejects energy to a low temperature body

D. None of the above

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4

Which of the following refrigerant is highly toxic and flammable?

A. Ammonia

B. Carbon dioxide

C. Sulphur dioxide

D. R-12

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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

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

Aqua ammonia is used as refrigerant in the following type of refrigeration system

A. Compression

B. Direct

C. Indirect

D. Absorption

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4

The superheated vapour region, in a pressure enthalpy chart, is represented by the space

A. To the left of saturated liquid line

B. To the right of saturated liquid line

C. Between the saturated liquid line and saturated vapour line

D. None of the above