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.

An open feedwater heater operates at steady state with liquid entering at inlet 1 with t? = 40°c and pl = 1 .2 mpa. water vapor att2-200°c and p2 = 1.2 mpa enters at inlet 2. saturated liquid water exits with a pressure of pa 1.2 mpa. neglect heat transfer with the surroundings and all kinetic and potential energy effects, determine the mass flow rate of steam at inlet 2 if the mass flow rate of liquid water at inlet 1 is given as 2 kg/s.