Thermal diffusivity of a substance is ____________________?

Question: A sphere of radius ‘R1’ is enclosed in a sphere of radius ‘R2’. The view (or shape) factor for radiative heat transfer of the outer sphere with respect to the inner sphere is
[A].

0

[B].

R2/(R1+R2)

[C].

1

[D].

(R1/R2)2

Answer: Option B

Explanation:

No answer description available for this question.

Question: In the equation Q = UAΔt; Δt is
[A].

geometric mean temperature difference.

[B].

arithmetic mean temperature difference.

[C].

logarithmic mean temperature difference.

[D].

the difference of average bulk temperatures of hot and cold fluids.

Answer: Option C

Explanation:

No answer description available for this question.

Question: Intermittant tube cleaning is possible to be done in case of a __________ evaporator.
[A].

basket type

[B].

horizontal tube

[C].

calendria

[D].

none of these

Answer: Option A

Explanation:

No answer description available for this question.