A butt-welded thermocouple (Fig. P. 7.35) having an emissivity of 0.8 is used to measure the temperature of a transparent gas flowing in a large duct whose walls are at 227°C. The temperature...

A butt-welded thermocouple (Fig. P. 7.35) having an emissivity of 0.8 is used to measure the temperature of a transparent gas flowing in a large duct whose walls are at 227°C. The temperature indicated by the thermocouple is 504°C. If the convection heat transfer coefficient between the surface of the couple and the gas is 142 W/m²
K, estimate the true gas temperature.