The data listed below are claimed for a power cycle operating between hot and cold reservoirs at 1200 K and 400 K, respectively. For each case, determine whether the cycle operates reversibly, operates irreversibly, or is impossible. a. Q = 900 kJ, Weycle = 450 kJ b. Q = 900 kJ, Q. = 300 kJ c. Weycle 600 kJ, Q = 400 kJ d. n = 75% 50% 66.7% 60%