ENGINEERINGTwo solid blocks, each having mass m and specific heat c, and initially at temperatures $T_1$ and $T_2,$ respectively, are brought into contact, insulated on their outer surfaces, and allowed to come into thermal equilibrium. a. Derive an expression for the exergy destruction in terms of m, c, $T_1, T_2,$ and the temperature of the environment, $T_0.$ b. Demonstrate that the exergy destruction cannot be negative. c. What is the source of exergy destruction in this case?