An electrical power plant manages to send 90% of the heat produced in the burning of fossil fuel into the water-to-steam conversion.Of the heat carried by the steam,40% is converted to the mechanical energy of the spinning turbine.Which of the following choices best describes the overall efficiency of the heat-to-work conversion in the plant (as a percentage)?

Question

An electrical power plant manages to send 90% of the heat produced in the burning of fossil fuel into the water-to-steam conversion.Of the heat carried by the steam,40% is converted to the mechanical energy of the spinning turbine.Which of the following choices best describes the overall efficiency of the heat-to-work conversion in the plant (as a percentage)?​

Quizplus · Accepted Answer

The overall efficiency is the product of the two efficiencies: 90% of the heat is used in the water-to-steam conversion, and 40% of that is converted to mechanical energy. So, the overall efficiency is 0.9 * 0.4 = 0.36 or 36%, which is less than 40%.

An Electrical Power Plant Manages to Send 90% of the Heat