Chemical Heat Transfer

Absorptivity and reflectivity of a perfect black body are respectively _______________?

Byadmin March 2, 2019August 24, 2021

Absorptivity and reflectivity of a perfect black body are respectively _______________?

A. 1 and 0
B. 0 and 1
C. 1 and ∞
D. 0 and 0.5

Chemical Heat Transfer

Among liquids, water has a comparatively high value of thermal conductivity, due to its__________________?

Among liquids, water has a comparatively high value of thermal conductivity, due to its__________________?

A. Low density
B. High viscosity
C. Partial ionisation
D. Dense structure

Read More Among liquids, water has a comparatively high value of thermal conductivity, due to its__________________?
Chemical Heat Transfer

In case of surface condensers, a straight line is obtained on plotting 1/U vs. ____________ on an ordinary graph paper?

In case of surface condensers, a straight line is obtained on plotting 1/U vs. ____________ on an ordinary graph paper?

A. 1/V̅ -0.8
B. V̅ -0.8
C. V̅ -2
D. 1/ V̅ -2

Read More In case of surface condensers, a straight line is obtained on plotting 1/U vs. ____________ on an ordinary graph paper?
Chemical Heat Transfer

The ratio of momentum diffusivity to thermal diffusivity is the ______________ number?

The ratio of momentum diffusivity to thermal diffusivity is the ______________ number?

A. Prandtl
B. Nusselt
C. Stanton
D. Grashoff

Read More The ratio of momentum diffusivity to thermal diffusivity is the ______________ number?
Chemical Heat Transfer

Extended heat transfer surface like fins are used to increase the heat transfer rate. Fin efficiency is defined as the ratio of heat transferred across the fin surface to the theoretical heat transfer across an equal area held at the________________?

Extended heat transfer surface like fins are used to increase the heat transfer rate. Fin efficiency is defined as the ratio of heat transferred across the fin surface to the theoretical heat transfer across an equal area held at the________________?

A. Surrounding temperature
B. Average temperature of the fin
C. Temperature of the fin end
D. Constant temperature equal to that of the base

Read More Extended heat transfer surface like fins are used to increase the heat transfer rate. Fin efficiency is defined as the ratio of heat transferred across the fin surface to the theoretical heat transfer across an equal area held at the________________?
Chemical Heat Transfer

Walls of a cubical oven are of thickness l, and they are made of material of thermal conductivity k. The temperature inside the oven is 100°C and the inside heat transfer coefficient is „3k/l’. If the wall temperature on the outside is held at 25°C, what is the inside wall temperature in degree centigrade ?

Walls of a cubical oven are of thickness l, and they are made of material of thermal conductivity k. The temperature inside the oven is 100°C and the inside heat transfer coefficient is „3k/l’. If the wall temperature on the outside is held at 25°C, what is the inside wall temperature in degree centigrade ?

A. 35.5
B. 43.75
C. 81.25
D. 48.25

Read More Walls of a cubical oven are of thickness l, and they are made of material of thermal conductivity k. The temperature inside the oven is 100°C and the inside heat transfer coefficient is „3k/l’. If the wall temperature on the outside is held at 25°C, what is the inside wall temperature in degree centigrade ?
Chemical Heat Transfer

Thermal diffusivity of a material __________________?

Thermal diffusivity of a material __________________?

A. Has the unit m2 /sec
B. Is defined as K/ρ . Cp
C. Is the ratio of thermal conductivity to thermal capacity
D. All A., B. and C.

Read More Thermal diffusivity of a material __________________?