A sinusoidal current has a frequency of 50 Hz. At one instant, the current is at its maximum value in one direction.
Which describes the current 0.030 s later?
Zero, after one full cycle.
Maximum in the same direction, after two full cycles.
Maximum in the opposite direction, after one and a half cycles.
Zero, after two and a half cycles.
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.