An AC mains adapter for a household internet router contains a transformer.
Suggest a suitable material for the core of this transformer.
The transformer has an input voltage of 230 V230\text{ V}230 V and a target output voltage of 11.5 V11.5\text{ V}11.5 V. There are 400040004000 turns on the input (primary) coil. Calculate the number of turns required on the output (secondary) coil.
Identify which of the following conditions poses the greatest hazard of an electric shock when plugging in the adapter: dry hands, wet hands, cold environment, or dusty surface.
275 exam-style questions on CIE IGCSE Physics 4.5 Electromagnetic effects, covering 4.5.1a Electromagnetic induction, 4.5.1b Direction of an induced e.m.f., 4.5.2 The a.c. generator, 4.5.3a Magnetic effect of a current and its applications, 4.5.3b Strength and direction of the field around wires and solenoids, 4.5.4a Force on a current-carrying conductor, 4.5.4b Force on beams of charged particles, 4.5.5 The d.c. motor, 4.5.6a Construction and operation of a transformer, 4.5.6b Turns ratio and current in a transformer, and 4.5.6c High-voltage transmission of electricity. Each one has a worked solution and a mark scheme showing where the marks go.