An electric toothbrush runs from a battery that provides a potential difference of 6.0 V across its motor. The current in the motor depends on how firmly the brush is pressed against the teeth. The table shows the current and the brushing time in four tests.
| Test | Current | Brushing time |
|---|---|---|
| A | 0.30 A | 120 s |
| B | 0.50 A | 60 s |
| C | 0.40 A | 60 s |
| D | 0.60 A | 45 s |
In which test does the toothbrush transfer 180 J of energy? Use E=IVtE=IVtE=IVt.
Test A
Test D
Test C
Test B
105 exam-style questions on Edexcel GCSE Physics 10.3 Electrical energy and power, covering 10.3.1 The heating effect of an electric current, 10.3.2 Reducing energy transfer in wires, 10.3.3 Advantages and disadvantages of the heating effect, 10.3.4 Energy transferred by an electrical circuit, 10.3.5 Electrical power, and 10.3.6 Energy transfers in domestic devices. Each one has a worked solution and a mark scheme showing where the marks go.