An electric motor operating at steady state draws a current of 10amps with a voltage of 220V. The output shaft power rotates at 1000RPM with a torque of 16N-m applied to an external load. The rate of heat transfer from the motor to its surroundings is related to the surface temperature Tb and the ambient temperature To by Newtonâ€^TMs Law of cooling; hA(Tb -To ) where h = 100W /(m^2 Ã-K), A = 0.195 m^2 and To = 293K .

a) Determine the surface temperature Tb in K? (For this one I got Tb = 406 K)

b) For the motor as the system, determine the rate of entropy production, in W/K.

c) If the system boundary is extended such that it contains enough of the nearby surroundings for heat transfer to take place at temperature To, determine the rate of entropy production, in W/K, for the enlarged system.

d) Explain any difference between the entropy production values form part b) and part c).