A theatre spotlight has an input power of 1.2 kW and an efficiency of 0.35. The spotlight is switched on for 4.0 minutes4.0\ \mathrm{minutes}4.0 minutes.
Calculate the energy dissipated in unwanted transfers while the spotlight is switched on.
128 exam-style questions on Edexcel GCSE Physics 8.3 Power and efficiency, covering 8.3.1 Power and 8.3.2 Efficiency. Each one has a worked solution and a mark scheme showing where the marks go.