With increase in temperature, the total emissivity of conductors____________________?

Related Mcqs:

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...

Dittus-Boelter equation used for the determination of heat transfer co-efficient is valid ___________________?

A. For fluids in laminar flow B. For fluids in turbulent flow C. When Grashoff number is very important D. For liquid metals...

Minimum recommended baffle spacing in a shell and tube heat exchanger is about (where, D = shell diameter)?

A. 0.2 D B. 0.5 D C. 0.66 D D. 0.80 D...

Electro-magnetic spectrum range, which is important for radiation varies from _____________ microns?

A. 1 to 100 B. 0.5 to 50 C. 10 to 100 D. 100 to 1000...

The film co-efficient is decreased due to the presence of non-condensing gases in the vapors. The film co-efficient of superheated vapor as compared to that of saturated vapor is___________________?

A. More B. Less C. Some D. Either more or less; depends on the nature of vapor...