Question

If you have a device that has an energy efficiency of 0.4 and you put in 100 units of energy, how many units of useful energy will you get out of it?

Answer 1

If its 0.4%, the answer will be 0.4

or else it will be 40. 

Answer 2

Answer:

40 units

Explanation:

efficiency, η = 0.4

Input Energy, Q1 = 100 units

Let output energy is Q2.

Efficiency is defined as the ratio of output energy to the input energy.

η = Q2 / Q1

Q2 = η x Q1

Q2 = 0.4 x 100 = 40 units