Temperature of 165°C, Volume = 4/3πr^3, and A = 4πr^2. Determine (a) the Biot number, (b) the time required for the thermocouple to indicate a change in temperature, p = 8750 kg/m^3, Cp = 380 J/kg°C, k_thermocouple = 28 W/m°C, h = 145 W/m^2°C. The thermal junction properties are: suddenly changes to and is maintained at T = 215°C. diameter. Initially, the junction and air temperature is T = 25°C. The air temperature. The temperature of an air stream flowing with a velocity of 3 m/s is measured by a thermocouple.