An electric water heater having a 100 liter capacity employs an electric resistor to heat water from 18 to 60°C. The outer surface of the resistor remains at an average temperature of 97°C. Heat transfer from the outside of the water heater is negligible and the states of the resistor and the tank holding the water do not change significantly. Modeling the water as incompressible, determine the amount of entropy produced, in kJ/K, for
(a) the water as the system.
(b) the overall water heater including the resistor.
Compare the results of parts (a) and (b), and discuss.