12–75 the emissivity of a tungsten filament can be approximated to be 0.5 for radiation at wavelengths less than 1 mm and 0.15 for radiation at greater than 1 mm. determine the average emissivity of the filament at (a) 2000 k and (b) 3000 k. also, determine the absorptivity and reflectivity of the filament at both temperatures.

On a average work day more than work place firs are reorted

Refrigerant 134a enters an insulated compressor operating at steady state as saturated vapor at -26°c with a volumetric flow rate of 0.18 m3/s. refrigerant exits at 9 bar, 70°c. changes in kinetic and potential energy from inlet to exit can be ignored. determine the volumetric flow rate at the exit, in m3/s, and the compressor power, in kw.

An air compression refrigeration system is to have an air pressure of 100 psia in the brine tank and an allowable air temperature increase of 60°f for standard vapor compression cycle temperatures of 77 f entering the expansion cylinder and 14 f entering the compression cylinder, calculate the coefficient of performance a. 2.5 b 3.3 c. 4.0 d. 5.0