Which of the following transformers can change a 240 V a.c. input into a 12 V a.c. output?
Primary coil of 600 turns600\text{ turns}600 turns, secondary coil of 30 turns30\text{ turns}30 turns
Primary coil of 800 turns800\text{ turns}800 turns, secondary coil of 50 turns50\text{ turns}50 turns
Primary coil of 1000 turns1000\text{ turns}1000 turns, secondary coil of 40 turns40\text{ turns}40 turns
Primary coil of 1200 turns1200\text{ turns}1200 turns, secondary coil of 80 turns80\text{ turns}80 turns
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.