An axhaust stack thermocouple is inserted into a 20 cm long well made of 5mm-O.D., 0.7 mm-wall-thicknes AISI 316 stainless steel tube and is held in good thermal contact with the sealed end by a spring-loaded plug. The convective heat transfer coefficient for the exhaust gases flowing across the tubing s estimated to be 65 W/m2K. If the thermocouple reading is 221 deg C when the stack walls are at 178 deg C determine the gas temperature.