Two electric irons are each tested for 50 s. The table shows the energy transfers during each test.
| Iron | Total energy transferred electrically | Energy transferred to the soleplate |
|---|---|---|
| A | 40 kJ | 33 kJ |
| B | 36 kJ | 32.5 kJ |
A shop will only stock an iron that transfers energy usefully at a rate of at least 640 W and wastes energy at a rate of no more than 120 W.
Which iron, if either, should the shop stock? Justify your answer with calculations.
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.