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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

Correct Answer :

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.


Related Questions

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4

The domestic refrigerator uses following type of compressor

A. Centrifugal

B. Axial

C. Miniature sealed unit

D. Piston type reciprocating

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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

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

In a domestic refrigerator, a capillary tube controls the flow of refrigerant from the

A. Expansion valve to the evaporator

B. Evaporator to the thermostat

C. Condenser to the expansion valve

D. Condenser to the evaporator

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4

The change in evaporator temperature in a refrigeration cycle, as compared to change in condenser temperature, influences the value of C.O.P.

A. More

B. Less

C. Equally

D. Unpredictable

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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

If a gas is to be liquefied, its temperature must be

A. Increased to a value above its critical temperature

B. Reduced to a value below its critical temperature

C. Equal to critical temperature

D. None of the above

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4

A heat pump working on a reversed Carnot cycle has a C.O.P. of 5. It works as a refrigerator taking 1 kW of work input. The refrigerating effect will be

A. 1 kW

B. 2 kW

C. 3 kW

D. 4 kW

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4

The refrigerant supplied to a compressor must be

A. Superheated vapour refrigerant

B. Dry saturated liquid refrigerant

C. A mixture of liquid and vapour refrigerant

D. None of these

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4

The power per tonne of refrigeration is

A. 3.5/C.O.P.

B. C.O.P/3.5

C. 3.5 × C.O.P.

D. None of these

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4

The C.O.P. of a heat pump working on a reversed Carnot cycle is

A. T₁/(T₂ - T₁)

B. (T₂ - T₁)/T₁

C. (T₁ - T₂)/T₁

D. T₂/(T₂ - T₁)

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4

Which of the following refrigerant has the highest freezing point.

A. Ammonia

B. Carbon dioxide

C. Sulphur dioxide

D. R-12

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4

The optimum effective temperature for human comfort is

A. Higher in winter than in summer

B. Lower in winter than in summer

C. Same in winter and summer

D. Not dependent on season

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4

A certain refrigerating system has a normal operating suction pressure of 10 kg/cm gauge and condensing pressure of about 67 kg/cm. The refrigerant used is

A. Ammonia

B. Carbon dioxide

C. Freon

D. Brine

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4

The temperature of ammonia after compression in a vapour compression system is

A. 20 to 50°C

B. 50 to 70°C

C. 70 to 110°C

D. None of these

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4

Air refrigeration operates on

A. Carnot cycle

B. Reversed Carnot cycle

C. Rankines cycle

D. Brayton cycle

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4

The wet bulb temperature during sensible cooling of air

A. Remains constant

B. Increases

C. Decreases

D. None of these

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4

The operating pressure for refrigerating units using R-12 as a refrigerant is

A. 2 bar

B. 8 bar

C. 15 bar

D. 30 bar

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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

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

During humidification process, __________ increases.

A. Wet bulb temperature

B. Relative humidity

C. Dry bulb temperature

D. Specific humidity

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4

In order to cool and dehumidify a stream of moist air, it must be passed over the coil at a temperature

A. Which lies between the dry bulb and wet bulb temperatures of the incoming stream

B. Which lies between the wet bulb and dew point temperatures of the incoming stream

C. Which is lower than the dew point temperature of the incoming stream

D. Of adiabatic saturation of incoming stream

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4

The thermal diffusivity for gases is generally __________ those for liquids.

A. Equal to

B. Less than

C. Greater than

D. None of these

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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

One ton refrigeration corresponds to

A. 50 kcal/ min

B. 50 kcal/ hr

C. 80 kcal/ min

D. 80 kcal/ hr

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4

The reciprocating refrigerant compressors are very suitable for

A. Small displacements and low condensing pressures

B. Large displacements and high condensing pressures

C. Small displacements and high condensing pressures

D. Large displacements and low condensing pressures

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4

The sensible heat factor during cooling and dehumidification process is given by (where h₁ = Enthalpy of air entering the cooling coil, h₂ = Enthalpy of air leaving the cooling coil, and hA = Enthalpy of air at the end of dehumidification process)

A. (hA - h2)/ (h1 - h2)

B. (h2 - hA)/ (h1 - h2)

C. (h1 - h2)/ (hA - h2)

D. (hA - h1)/ (h2 - h1)

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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

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4

In a vapour absorption refrigeration system, the compressor of the vapour compression system is replaced by

A. Liquid pump

B. Generator

C. Absorber and generator

D. Absorber, generator and liquid pump

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4

One ton of the refrigeration is

A. The standard unit used in refrigeration problems

B. The cooling effect produced by melting 1 ton of ice

C. The refrigeration effect to freeze 1 ton of water at 0°C into ice at 0°C in 24 hours

D. The refrigeration effect to produce 1 ton of ice at NTP conditions