40% of incident radiant energy on the surface of a thermally transparent body is reflected back. If the transmissivity of the body be 0.15, then the emissivity of surface is____________________?

Related Mcqs:

Heat transfer in liquid and gases takes place by_____________________?

A. conduction B. convection C. radiation D. conduction and convection E. convection and radiation...

Which of the following has least value of conductivity_________________?

A. glass B. water C. plastic D. rubber E. air...

In heat exchangers, degree of approach is defined as the difference between temperatures of________________?

A. cold water inlet and outlet B. hot medium inlet and outlet C. hot medium outlet and cold water inlet D. hot medium outlet and cold water outlet E. none of the above...

Total emissivity of polished silver compared to black body is___________________?

A. same B. higher C. more or less same D. very much lower E. very much higher...

According to Stefan’s law, the total radiation from a black body per second per unit area is proportional to____________________?

A. absolute temperature B. T2 C. T5 D. t E. l/T...