A household refrigerator operates with cold- and hot-temperature reservoirs of Tc = 5°C and Th = 25°C, respectively. When new, the cold and hot side resistances are Rc,n = 0.05 K/W and Rh,n = 0.04 K/W, respectively. Over time, dust accumulates on the refrigerator's con- denser coil, which is located behind the refrigerator, increasing the hot side resistance to Rh,d = 0.1 K/W. It is desired to have a refrigerator cooling rate of qin = 750 W. Using the results of Problem 1.38, determine the modified coefficient of performance and the required power input W under (a) clean and (b) dusty coil conditions.