JAMB Physics 2018 Paper

Concept:Efficiency is the ratio of useful energy output to the total energy input.Explanation:In the energy flow through a hydroelectric power station, $E_1$ is the initial energy available, $E_2$ is the energy input into the machine, and $E_3$ is the useful energy output.Efficiency is calculated using:$$\text{Efficiency} = \frac{\text{useful energy output}}{\text{energy input}}$$Substituting the given energy values:$$\text{Efficiency} = \frac{E_3}{E_2}$$This matches option B.Answer:$\frac{E_3}{E_2}$ (Option B)