A motor receives 1000 J during a test. The table shows its unwanted transfers.
| Unwanted transfer | Energy in J\mathrm{J}J |
|---|---|
| Heating due to friction | 240 |
| Other heating | 120 |
| Sound | 40 |
A modification halves only the transfer due to friction. Total energy input remains 1000 J.
What is the new efficiency?
72%72\%72%
60%60\%60%
76%76\%76%
80%80\%80%
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.