A thermocouple used to measure the temperature of hot air flowing in a duct whose walls ar...

A thermocouple used to measure the temperature of hot air flowing in a duct whose walls are maintained at Tw = 500 K shows a temperature reading of Tth = 850 K. Assuming the emissivity of the thermocouple junction to be ε = 0.6 and the convection heat transfer coefficient to be h = 75 W/m2·K, determine the actual temperature of air. Answer: 1066 K