A computer code is being developed to analyze a 12.5-mm-diameter, cylindrical sensor used to determine ambient air temperature. The sensor experiences free convection while positioned horizontally in quiescent air at T∞ = 27°C. For the temperature range from 30 to 80°C, derive an expression for the convection coefficient as a function of only ?T - Ts - T∞, where Ts is the sensor temperature. Evaluate properties at an appropriate film temperature and show what effect this approximation has on the convection coefficient estimate.