A process has a total energy input $E_{in}$, with part of it being converted into useful energy output $U$ and the rest being transferred to wasted energy $W$. What efficiency does the process have?
- A$\dfrac{U}{E_{in}} \times 100\%$
- B$\dfrac{W}{E_{in}} \times 100\%$
- C$\dfrac{U}{W} \times 100\%$
- D$\dfrac{U + W}{E_{in}} \times 100\%$