Question

Pick the best description of energy efficiency?

A efficiency is equal to the ratio of energy you put into the energy you get out
B efficiency is equal to the ratio of energy you get out to the energy you put in
C efficiency is equal to the sum of the energy you put into the energy you get out

Answer 1

The answer is B. Efficiency is equal to the ratio of energy you get out (output) to the energy you put in (input). Say for a basic example you got a converted output of 40W from 50W input, you'll have an efficiency of 80 percent only.