The table shows the energy transfers for a machine before and after a modification.
| Test | Total energy input in J\mathrm{J}J | Useful energy output in J\mathrm{J}J |
|---|---|---|
| Before | 500 | 300 |
| After | 800 | 520 |
Which statement is correct?
Efficiency increases, and wasted energy per test decreases.
Efficiency increases, but wasted energy per test also increases.
Efficiency decreases, but wasted energy per test also decreases.
Efficiency decreases, and wasted energy per test increases.
100 exam-style questions on Edexcel GCSE Physics 3.2 Dissipation and efficiency, covering 3.2.1 Dissipation of energy, 3.2.2 Reducing unwanted energy transfers, 3.2.3 Efficiency, and 3.2.4 Increasing efficiency. Each one has a worked solution and a mark scheme showing where the marks go.