Question

energy efficiency = useful energy output/total energy input × 100 (%) if a power plant uses 100 units of energy to create electricity and the useful output is 5 units, what happens to the other 95% of the energy input? its lost as a gas. its lost as a liquid. its lost mostly as heat.

Explanation:

In energy systems, especially power plants, energy inefficiencies often result in energy being lost as heat due to factors like friction, waste heat from processes, etc. Loss as gas or liquid is not the primary way unused energy is lost in such contexts.

Answer:

C. It's lost mostly as heat. (Note: Assuming the options are labeled A, B, C with A: It's lost as a gas, B: It's lost as a liquid, C: It's lost mostly as heat)