Heat Transfer

Question: Heat transfer rate per unit area is called
[A].

thermal conductivity

[B].

heat flux

[C].

heat transfer co-efficient

[D].

thermal diffusivity

Answer: Option B

Explanation:

No answer description available for this question.

Question: Kirchoff s law applies to __________ radiation.
[A].

total

[B].

monochromatic

[C].

both (a) & (b)

[D].

neither (a) nor (b)

Answer: Option C

Explanation:

No answer description available for this question.

Question: With increase in porosity, the thermal conductivity of a solid substance
[A].

increases

[B].

decreases

[C].

remains unchanged

[D].

may increase or decrease; depends on the solid

Answer: Option B

Explanation:

No answer description available for this question.

Question: Maximum heat transfer rate is achieved in __________ flow.
[A].

co-current

[B].

counter-current

[C].

turbulent

[D].

laminar

Answer: Option C

Explanation:

No answer description available for this question.

Question: In case of heat transfer by conduction in a hollow cylinder, __________ mean area is used to calculate the heat transfer rate.
[A].

geometric

[B].

arithmetic

[C].

logarithmic

[D].

either (a), (b) or (c)

Answer: Option C

Explanation:

No answer description available for this question.

Question: At constant temperature, the thermal conductivities of gases __________ with rise in pressure.
[A].

decrease

[B].

increase

[C].

remain unchanged

[D].

may increase or decrease; depends on the pressure

Answer: Option A

Explanation:

No answer description available for this question.

Question: In Fourier’s law, the proportionality constant is called the
[A].

heat transfer co-efficient

[B].

thermal diffusivity

[C].

thermal conductivity

[D].

Stefan-Boltzman constant

Answer: Option C

Explanation:

No answer description available for this question.

Question: Boiling of milk in an open vessel is an example of __________ boiling.
[A].

film

[B].

sub-cooled

[C].

saturated nucleate

[D].

none of these

Answer: Option A

Explanation:

No answer description available for this question.

Question: Film boiling occurs at __________ pressure.
[A].

atmospheric

[B].

sub-atmospheric

[C].

negative

[D].

very high

Answer: Option D

Explanation:

No answer description available for this question.

Question: Heat flux, as defined in heat flow is analogous to __________ in electricity flow.
[A].

current

[B].

voltage

[C].

resistance

[D].

none of these

Answer: Option A

Explanation:

No answer description available for this question.