An engineer redesigns four current-carrying coil assemblies used to operate irrigation valves. The size and shape of each coil remain unchanged. The table compares each original assembly with its redesigned version.
| Coil assembly | Original number of turns | Original material inside the coil | Original current in A | Redesigned number of turns | Redesigned material inside the coil | Redesigned current in A |
|---|---|---|---|---|---|---|
| P | 300 | plastic | 0.50 | 600 | iron | 1.0 |
| Q | 600 | iron | 0.50 | 300 | plastic | 1.0 |
| R | 300 | iron | 1.0 | 600 | plastic | 0.50 |
| S | 600 | plastic | 1.0 | 300 | iron | 0.50 |
Which coil assembly is certain to produce a stronger magnetic field after it is redesigned?
S
P
Q
R
90 exam-style questions on AQA GCSE Physics 7.2 The motor effect, covering 7.2.1 Electromagnetism, 7.2.2 Fleming's left-hand rule (HT only), 7.2.3 Electric motors (HT only), and 7.2.4 Loudspeakers (HT only). Each one has a worked solution and a mark scheme showing where the marks go.