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Question: (NGr x NPr) is called the __________ number.
[A].

Graetz

[B].

Reyleigh

[C].

Nusselt

[D].

Stanton

Answer: Option B

Explanation:

No answer description available for this question.

Question: According to Reynolds analogy, Stanton number is equal to (where, f = Fanning friction factor)
[A].

2f

[B].

f

[C].

f/2

[D].

f/4

Answer: Option C

Explanation:

No answer description available for this question.

Question: Nusselt number for full developed, laminar, constant property flow in a pipe at uniform heat flux is
[A].

0.72

[B].

4.364

[C].

18

[D].

83

Answer: Option B

Explanation:

No answer description available for this question.

Question: Duhring rule is important in solving problems on
[A].

distillation

[B].

crystallisation

[C].

evaporation

[D].

humidification

Answer: Option C

Explanation:

No answer description available for this question.

Question: For specified tube outside diameter, higher BWG means higher
[A].

tube thickness

[B].

cross-sectional area

[C].

weight per unit length

[D].

none of these

Answer: Option B

Explanation:

No answer description available for this question.

Question: A body is called grey if the monochromatic emissivity of the body is
[A].

zero

[B].

unity

[C].

same for all wavelengths

[D].

different for all wavelengths

Answer: Option C

Explanation:

No answer description available for this question.

Question: With increase in temperature, the thermal conductivity of a gas
[A].

increases.

[B].

decreases.

[C].

remains same.

[D].

may increase or decrease depending on the type of gas.

Answer: Option A

Explanation:

No answer description available for this question.

Question: “The ratio of the total emissive power to the absorptivity for all bodies is same at ther-mal equilibrium”. This is __________ law.
[A].

Kirchoffs

[B].

Planck’s

[C].

Wien’s displacement

[D].

Stefan-Boltzman

Answer: Option A

Explanation:

No answer description available for this question.

Question: Absorptivity and refletivity of a perfect black body are respectively
[A].

1 and 0

[B].

0 and 1

[C].

1 and ∞

[D].

0 and 0.5

Answer: Option A

Explanation:

No answer description available for this question.

Question: In a liquid-liquid heat exchanger, for the same process temperature, the ratio of the LMTD in parallel flow to the LMTD in counter flow is always
[A].

< 1

[B].

> 1

[C].

1

[D].

∞

Answer: Option A

Explanation:

No answer description available for this question.