In one month, a solar panel array on a house roof generates 360 kWh of useful electrical energy.
The efficiency of the solar panel array is 0.20.
What is the wasted energy in one month?
Use the equation:
efficiency=useful output energy transferinput energy transfer \text{efficiency} = \frac{\text{useful output energy transfer}}{\text{input energy transfer}} efficiency=input energy transferuseful output energy transfer72 kWh72\text{ kWh}72 kWh
1440 kWh1440\text{ kWh}1440 kWh
1800 kWh1800\text{ kWh}1800 kWh
2160 kWh2160\text{ kWh}2160 kWh
37 exam-style questions on OCR GCSE Physics Power and efficiency. Each one has a worked solution and a mark scheme showing where the marks go.