A metal toaster is connected to the mains electrical supply. The metal outer casing is connected to the earth wire. A fault causes the live wire to come loose and contact the inner surface of the metal casing.
The toaster is switched on. A short circuit causes a very large current to flow in the live wire. Explain the hazard of this large electric current.
Explain how a fuse in the live wire helps protect against the danger of a large electric current.
Explain why the appliance is not safe to use if the fuse is connected into the neutral wire instead of the live wire.
The electric current in a different kitchen appliance when operating normally is 7.5 A7.5\text{ A}7.5 A. State a suitable rating for its fuse. Choose one of these standard values: 3 A3\text{ A}3 A, 5 A5\text{ A}5 A, 10 A10\text{ A}10 A and 13 A13\text{ A}13 A.
A portable car heater has a potential difference of 12 V12\text{ V}12 V (d.c.) across its heating element. The current in the heating element is 1.6 A1.6\text{ A}1.6 A. Calculate the resistance of this heating element.
135 exam-style questions on CIE IGCSE Physics Electrical safety, covering Electrical safety. Each one has a worked solution and a mark scheme showing where the marks go.