(a) carefully explain the difference between irreversible and reversible processes. also explain what the second law of thermodynamics dictates about reversible processes. (you may find it to compare water freezing at 0 °c and super- cooled water freezing at-5 °c.) [5 marks a heat engine operates with an efficiency n = 0.30 between two energy reservoirs at temperatures of 450 k and 293 k. the engine does 90 j of work per cycle. (b) draw and label a diagram to represent the engine and find the heat flows (i) out of the hot reservoir; and (ii) into the cold reservoir. [2 marks] (c) what is the maximum efficiency for an engine operating between the two reser- voirs? [1 mark] an experimental engineer decides to operate the engine as a heat pump using the same two energy reservoirs. electric power is supplied to turn the engine at a rate of 0.9 kw, doing 90 j of work per cycle. she finds that the heat pump delivers heat to the hot reservoir at a rate of 2.35 kw. [1 mark] (d) how many cycles does the heat pump perform per minute? (e) draw and label a diagram to represent the heat pump and find the heat flows (i) into the hot reservoir; and (ii) out of the cold reservoir. [2 marks] (f) find the coefficient of performance of the heat pump as well as the maximum coefficient of performance for a heat pump operating between the two reservoirs. comment on any difference between the real value and the maximum