A hybrid vehicle engine has an input power of 120 kW. Its thermal efficiency is 35%. Which option correctly shows the values for the useful output power and the wasted power of this engine?
Useful power = 78 kW78\text{ kW}78 kW, Wasted power = 42 kW42\text{ kW}42 kW
Useful power = 42 kW42\text{ kW}42 kW, Wasted power = 78 kW78\text{ kW}78 kW
Useful power = 35 kW35\text{ kW}35 kW, Wasted power = 85 kW85\text{ kW}85 kW
Useful power = 42 kW42\text{ kW}42 kW, Wasted power = 120 kW120\text{ kW}120 kW
37 exam-style questions on OCR GCSE Physics Power and efficiency. Each one has a worked solution and a mark scheme showing where the marks go.