An electric toy car is powered by an electric motor and a rechargeable battery.
The electric motor consists of a current-carrying coil in a magnetic field. The manufacturer wants to increase the turning effect of the coil to make the toy car accelerate faster.
State three ways of increasing the turning effect of the coil.
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The toy car can drive both forwards and backwards. State what must happen to the current in the coil to reverse the direction of rotation.
The battery is charged by plugging it into a mains transformer. The primary voltage VpV_pVp of the transformer is 240 V240\text{ V}240 V and the secondary voltage VsV_sVs is 12 V12\text{ V}12 V.
The number of turns on the primary coil NpN_pNp is 320032003200 turns.
Calculate the number of turns on the secondary coil, NsN_sNs.
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.