A heater has a power of 500 W. During a period of 3.0 min, it is switched off for a total of 40 s. What is the energy transferred to the heater during this period?
110 kJ110\ \mathrm{kJ}110 kJ
90 kJ90\ \mathrm{kJ}90 kJ
70 kJ70\ \mathrm{kJ}70 kJ
20 kJ20\ \mathrm{kJ}20 kJ
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.