A kettle operates at 2.0 kW for 3.0 minutes3.0\ \mathrm{minutes}3.0 minutes. A charger operates at 20 W for 4.0 hours4.0\ \mathrm{hours}4.0 hours. Which comparison of total energy transferred is correct?
The kettle transfers 72 kJ72\ \mathrm{kJ}72 kJ more.
The charger transfers 280 kJ280\ \mathrm{kJ}280 kJ more.
The kettle transfers 280 kJ280\ \mathrm{kJ}280 kJ more.
The charger transfers 72 kJ72\ \mathrm{kJ}72 kJ more.
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.