27. IE •• A perfectly isolated system consists of two large thermal reservoirs at constant temperatures of 100 °C and 0 °C. Assume the reservoirs make contact and 1000 J of heat flowed from the cold reservoir to the hot reservoir spontaneously with no appreciable reservoir temperature changes.

(a) The total change in entropy of this isolated system (both reservoirs) would be (1) positive, (2) zero,

(3) negative. Explain.

(b) Calculate the total change in entropy of this isolated system.