A lamp has its switch incorrectly connected in the neutral wire. The switch is open, and the lamp is not lit.
Why can touching a metal part connected to the live side of the lamp still be dangerous?
The open switch increases the current through the filament.
The neutral wire changes into an earth wire when the switch opens.
The live connection can drive a current through a person to earth.
The filament stores the mains current after the switch opens.
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.