Some processes are more efficient than others. Which expression represents the efficiency of a process?
- A$\dfrac{\text{total energy output}}{\text{total energy input}} \times 100\%$
- B$\dfrac{\text{useful energy output}}{\text{total energy input}} \times 100\%$
- C$\dfrac{\text{wasted energy output}}{\text{total energy input}} \times 100\%$
- D$\dfrac{\text{wasted energy output}}{\text{useful energy output}} \times 100\%$