A voltage sensor records consecutive positive peaks from a supply at 12 ms, 32 ms and 52 ms. A negative peak occurs halfway between each pair of positive peaks.
Which pair gives the supply frequency and the interval between consecutive current reversals in a resistor?
50 Hz50\ \mathrm{Hz}50 Hz and 10 ms10\ \mathrm{ms}10 ms.
50 Hz50\ \mathrm{Hz}50 Hz and 20 ms20\ \mathrm{ms}20 ms.
25 Hz25\ \mathrm{Hz}25 Hz and 10 ms10\ \mathrm{ms}10 ms.
25 Hz25\ \mathrm{Hz}25 Hz and 20 ms20\ \mathrm{ms}20 ms.
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.