A digital radio is used for 4.0 h each day. When it is not being used, it would remain on standby at 3.5 W.
A timer leaves the radio on standby for 1.0 h after use and then disconnects it from the mains for the rest of the day.
Electricity costs 28 p28\ \mathrm{p}28 p per kWh\mathrm{kWh}kWh.
Calculate the money saved by using the timer for 365 days, compared with leaving the radio on standby whenever it is not being used.
Give your answer in pounds.
81 exam-style questions on Edexcel GCSE Physics 10.4 Mains electricity, covering 10.4.1 Direct and alternating current, 10.4.2 Live, neutral and earth wires; safety, 10.4.3 Mains wire potential differences and dangers, and 10.4.4 Power ratings and energy use. Each one has a worked solution and a mark scheme showing where the marks go.