A 50 kg iron block and 20 kg copper block, both initially at 80 °C, are dropped into a large lake at 15 °C. Thermal equilibrium is established after a while as a result of heat transfer between the blocks and the lake water. Assuming an average specific heat of 0.45 kJ/kg K and 0.39 kJ/kg K for the iron block and the copper block, respectively. (a) Determine the entropy change of the iron block (b) Determine the entropy change of the copper block (c) Determine the heat transfer to the lake (d) Determine the entropy change of the lake (e) Determine the entropy generation during this process.