Home
Current Affairs January 2024

What is the correct answer?

4

A reversible engine has ideal thermal efficiency of 30%. When it is used as a refrigerating machine with all other conditions unchanged, the coefficient of performance will be

A. 1.33

B. 2.33

C. 3.33

D. 4.33

Correct Answer :

B. 2.33


Related Questions

What is the correct answer?

4

If the evaporator temperature of a plant is lowered, keeping the condenser temperature constant, the h.p. of compressor required will be

A. Same

B. More

C. Less

D. More/less depending on rating

What is the correct answer?

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

What is the correct answer?

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

What is the correct answer?

4

The condition of refrigerant after passing through the expansion or throttle valve, in a vapour compression system is

A. High pressure saturated liquid

B. Wet vapour

C. Very wet vapour

D. Dry vapour

What is the correct answer?

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

What is the correct answer?

4

During sensible cooling of air ________ decreases.

A. Wet bulb temperature

B. Relative humidity

C. Dry bulb temperature

D. Specific humidity

What is the correct answer?

4

During humidification process, dry bulb temperature

A. Remains constant

B. Increases

C. Decreases

D. None of these

What is the correct answer?

4

The boiling point of ammonia is

A. 100°C

B. 50°C

C. 33.3°C

D. 0°C

What is the correct answer?

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

What is the correct answer?

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

What is the correct answer?

4

A vapour absorption refrigerator uses __________ as a refrigerant.

A. Water

B. Ammonia

C. Freon

D. Aqua-ammonia

What is the correct answer?

4

A refrigeration cycle operates between condenser temperature of + 27°C and evaporator temperature of -23°C. The Carnot coefficient of performance of cycle will be

A. 0.2

B. 1.2

C. 5

D. 6

What is the correct answer?

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

What is the correct answer?

4

During dehumidification process, the relative humidity

A. Remains constant

B. Increases

C. Decreases

D. None of these

What is the correct answer?

4

The moisture in a refrigerant is removed by

A. Evaporator

B. Safety relief valve

C. Dehumidifier

D. Driers

What is the correct answer?

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

What is the correct answer?

4

The relative humidity is defined as

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

What is the correct answer?

4

For better C.O.P of refrigerator, the pressure range corresponding to temperature in evaporator and condenser must be

A. Small

B. High

C. Equal

D. Anything

What is the correct answer?

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

What is the correct answer?

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

What is the correct answer?

4

The coefficient of performance is the ratio of the refrigerant effect to the

A. Heat of compression

B. Work done by compressor

C. Enthalpy increase in compressor

D. All of the above

What is the correct answer?

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

What is the correct answer?

4

The C.O.P. of a refrigerator working on a reversed Carnot cycle is (where T₁ = Lowest absolute temperature, and T₂ = Highest absolute temperature)

A. T₁ / (T₂ - T₁)

B. (T₂ - T₁)/T₁

C. (T₁ - T₂)/T₁

D. T₂/ (T₂ - T₁)

What is the correct answer?

4

Highest temperature encountered in refrigeration cycle should be

A. Near critical temperature of refrigerant

B. Above critical temperature

C. At critical Temperature

D. Much below critical temperature

What is the correct answer?

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

What is the correct answer?

4

Freon group of refrigerants are

A. Inflammable

B. Toxic

C. Non-inflammable and toxic

D. Nontoxic and non-inflammable

What is the correct answer?

4

In case of sensible heating of air, the coil efficiency is given by (where B.P.F. = Bypass factor)

A. B.P.F. - 1

B. 1 - B. P.F.

C. 1/ B.P.F.

D. 1 + B.P.F.

What is the correct answer?

4

Chaperon equation is applicable for registration at

A. Saturation point of vapour

B. Saturation point of liquid

C. Sublimation temperature

D. Triple point

What is the correct answer?

4

One tonne of refrigeration (1TR) means that the heat removing capacity is

A. 21 kJ/min

B. 210 kJ/min

C. 420 kJ/min

D. 620 kJ/min

What is the correct answer?

4

The centrifugal compressors are generally used for refrigerants that require

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