Refrigeration and Air Conditioning

Question: The C.O.P. of a Carnot refrigerator in winter will be __________ as compared to C.O.P. in summer.
[A].

same

[B].

lower

[C].

higher

Answer: Option C

Explanation:

No answer description available for this question.

Question: A one tonne refrigerating machine means that
[A].

one tonne is the total mass of machine

[B].

one tonne refrigerant is used

[C].

one tonne of water can be converted into ice

[D].

one tonne of ice when melts from and at 0° C in 24 hours, the refrigeration effect is equivalent to 210 kJ/min

Answer: Option D

Explanation:

No answer description available for this question.

Question: 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

Answer: Option B

Explanation:

No answer description available for this question.

Question: 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

Answer: Option A

Explanation:

No answer description available for this question.

Question: According to Stefan-Boltzmann law, the total radiation from a black body per second per unit area is directly proportional to the
[A].

absolute temperature

[B].

square of the absolute temperature

[C].

cube of the absolute temperature

[D].

fourth power of the absolute temperature

Answer: Option D

Explanation:

No answer description available for this question.

Question: According to Stefan’s law, the total radiation from a black body per second per unit area is directly proportional to the fourth power of the absolute temperature.
[A].

Correct

[B].

Incorrect

Answer: Option A

Explanation:

No answer description available for this question.

Question: Kirchhoff’s law states that
[A].

the total radiation from a black body per second per unit area is directly proportional to the fourth power of the absolute temperature

[B].

the wave length corresponding to the maximum energy is proportional to the absolute temperature

[C].

the ratio of the emissive power and absorptive power of all bodies is the same and is equal to the emissive power of a perfectly black body

[D].

none of the above

Answer: Option C

Explanation:

No answer description available for this question.

Question: According to Prevost’s theory of exchanges, every body irrespective of its temperature continuously emit heat radiations to the surrounding bodies and at the same time receives heat radiations from the surrounding bodies.
[A].

True

[B].

False

Answer: Option A

Explanation:

No answer description available for this question.

Question: For a white body, absorptivity (α ) = 0, reflectivity (ρ) = 1 and transmittivity (τ) = 0.
[A].

Correct

[B].

Incorrect

Answer: Option A

Explanation:

No answer description available for this question.

Question: An infinite parallel planes with emissivities e1 and e2, the interchange factor for radiation from surface 1 to surface 2 is given by
[A].

[B].

[C].

e1 + e2

[D].

e1e2

Answer: Option A

Explanation:

No answer description available for this question.