Refrigeration And Air Conditioning MCQ Questions & Answers

Refrigeration And Air Conditioning MCQ Questions & Answers | Mechanical Engineering

Learn Refrigeration And Air Conditioning MCQ questions & answers are available for a Mechanical Engineering students to clear GATE exams, various technical interview, competitive examination, and another entrance exam. Refrigeration And Air Conditioning MCQ question is the important chapter for a Mechanical Engineering and GATE students. Page-6 section-3

Condensing temperature in a refrigerator is the temperature

A) Of cooling medium B) Of freezing zone C) Of evaporator D) At which refrigerant gas becomes liquid

Discuss

Answer & Solution

Answer: Option D

Solution:

Condensing temperature in a refrigerator is the temperature At which refrigerant gas becomes liquid

In aircraft, air refrigeration Cycle is used because of

A) Low weight per tonne of refrigeration B) High heat transfer rate C) Low temperature at high altitudes D) Higher coefficient of performance

Discuss

Answer & Solution

Answer: Option A

Solution:

In aircraft, air refrigeration Cycle is used because of Low weight per tonne of refrigeration

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

Discuss

Answer & Solution

Answer: Option D

Solution:

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

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

A) 1.25 B) 0.8 C) 0.5 D) 0.25

Discuss

Answer & Solution

Answer: Option D

Solution:

Efficiency of a Carnot engine is given as 80% or $$\eta $$ = 0.80
If the cycle direction be reversed
The relation between the effecicy and C.O.P. is defined by formula
$${\text{C}}{\text{.O}}{\text{.P}}{\text{.}} = \frac{{1 - \eta }}{\eta } = \frac{{1 - 0.80}}{{0.80}} = 0.25$$

During sensible cooling,

A) Relative humidity remains constant B) Wet bulb temperature increases C) Specific humidity increases D) Partial pressure of vapour remains constant

Discuss

Answer & Solution

Answer: Option D

Solution:

During sensible cooling process the dry bulb (DB) temperature and wet bulb (WB) temperature of the air reduces, while the latent heat of the air, and the dew point (DP) temperature of the air remains constant.
In general the sensible cooling process is carried out by passing the air over the coil.

During sensible cooling of air, specific humidity

A) Remains constant B) Increases C) Decreases D) None of these

Discuss

Answer & Solution

Answer: Option A

Solution:

During sensible cooling of air, specific humidity Remains constant

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

A) Compression B) Expansion C) Condensation D) Evaporation

Discuss

Answer & Solution

Answer: Option D

Solution:

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

The COP of a domestic refrigerator

A) Is less than 1 B) Is more than 1 C) Is equal to 1 D) Depends upon the make

Discuss

Answer & Solution

Answer: Option B

Solution:

The COP of a domestic refrigerator is the ratio of the refrigeration capacity to the energy supplied to the compressor.
The COP of a domestic refrigerator Is more than 1

Accumulators should have adequate volume to store refrigerant charge at least

A) 10% B) 25% C) 50% D) 75%

Discuss

Answer & Solution

Answer: Option C

Solution:

Accumulators should have adequate volume to store refrigerant charge at least 50%

Which of the following refrigerant has the highest freezing point.

A) Ammonia B) Carbon dioxide C) Sulphur dioxide D) R-12

Discuss

Answer & Solution

Answer: Option C

Solution:

Sulphur dioxide has the highest freezing point.

Freezing point of Ammonia is −77.7 °C
Freezing point of Carbon dioxide is −78.5 °C
Freezing point of Sulphur dioxide is −72 °C
Freezing point of R-12 is −157.7 °C