A particular power plant operates with a heat-source reservoir at 350°C and a hea sink reservoir at 30°C. It has a thermal efficiency equal to 55% of the Carnot-engine thermal efficiency for the same temperatures. (a) What is the thermal efficiency of the plant? (b) To what temperature must the heat-source reservoir be raised to increase the ther mal efficiency of the plant to 35%? Again n is 55% of the Carnot-engine value.