Physics (AS & A Level) · Feb / March 2022 · Paper 12 · Question 15

The total energy input $E_{in}$ in a process is partly transferred to useful energy output $U$ and partly transferred to energy that is wasted $W$. What is the efficiency of the process?

1. A$\dfrac{U}{E_{in}} \times 100\%$
2. B$\dfrac{W}{E_{in}} \times 100\%$
3. C$\dfrac{U}{W} \times 100\%$
4. D$\dfrac{U+W}{E_{in}} \times 100\%$

As printed in the paper