28. IE •• Two large heat reservoirs at temperatures 200 °C and 60 °C, respectively, are brought into thermal contact, and 1.5 × 103 J of heat spontaneously flows from one to the other with no significant temperature change.

(a) The change in the entropy of the tworeservoir system is (1) positive, (2) zero, (3) negative.

Explain.

(b) Calculate the change in the entropy of the two-reservoir system.