4. A power plant operates at steady state, which causes the shaft from its steam turbine to rotate as shown below. This shaft is connected to a turbogenerator to generate electricity, producing current at 230 amp with a voltage of 13,000 V. The rate of heat transfer between the turbogenerator and its surroundings is related to its surface temperature T and the (lower) ambient temperature TO and is given by Q = hA(Tb -To), where h = 110 W/m.K, A = 32 m, and To= 298 K. a) Write down what this heat transfer equation describes. b) Determine the turbogenerator surface temperature Tb, in K. c) For the turbogenerator as the system, determine the rate of entropy production, in kW/K. Steam inlet Turbine Steam exit Turbogenerator input shaft A dal = 1800 RPM Torque - 16,700 N-m Turbogenerator Electricity i-230 amp Voltage = 13,000 V