An electric kettle is supplied with 360 kJ of energy. The thermal store of the water in the kettle increases by 306 kJ.
Calculate the efficiency of the kettle.
The body of the kettle is made from a plastic with double walls and a layer of air between them.
Explain how this design increases the efficiency of the kettle.
A student says:
'In winter, when the kitchen needs heating, this kettle is 100% efficient.'
Discuss whether the student is correct.
100 exam-style questions on Edexcel GCSE Physics 3.2 Dissipation and efficiency, covering 3.2.1 Dissipation of energy, 3.2.2 Reducing unwanted energy transfers, 3.2.3 Efficiency, and 3.2.4 Increasing efficiency. Each one has a worked solution and a mark scheme showing where the marks go.