Efficiency of electrical power plant

[ariana0923]

Homework Statement

An electrical power plant manages to transfer 88 percent of the heat produced in the burning of fossil fuel to convert water to steam. Of the heat carried by the steam, 40 percent is converted to the mechanical energy of the spinning turbine. Which best describes the overall efficiency of the heat-to-work conversion in the plant?

--> greater than 88 percent
--> 88 percent
--> 40 percent
--> less than 40 percent

Homework Equations

eff = 1 - (Qc/Qh)

The Attempt at a Solution

Uhh..? No idea lol, I tried using this equation but I got like .54 (when i plugged in .40 for Qc and .88 for Qh)

 

[mgb_phys]

Efficiencies multiply, if you have a source that is 50% that drives another stage that is 50% then overall you have 25%

 

[tomcue]

which doesn't seem right.

I would say that the overall efficiency of the heat-to-work conversion in the plant is greater than 88 percent. This is because the given information states that 88 percent of the heat produced is transferred to convert water to steam, and then 40 percent of the heat carried by the steam is converted to mechanical energy. This means that the overall efficiency is the product of these two efficiencies, which would be greater than 88 percent. However, without knowing the specific equations and calculations used in the plant, it is difficult to determine the exact efficiency.