A long coil is used to produce a magnetic field in a chamber. A constant current flows in the coil.
A probe measures the magnetic flux density and field direction at five positions inside the coil.
| Position relative to the centre of the coil in cm | Magnetic flux density in mT | Field direction |
|---|---|---|
| -10 | 1.24 | towards end P |
| -5 | 1.25 | towards end P |
| 0 | 1.26 | towards end P |
| 5 | 1.25 | towards end P |
| 10 | 1.24 | towards end P |
The probe is then placed at the centre of a single circular turn of wire. The turn has the same diameter as the long coil and carries the same current. The magnetic flux density is 0.013 mT.
Describe what the measurements show about the magnetic field inside the long coil. Compare the field inside the long coil with the field at the centre of the single turn.
Give the reason why the magnetic flux density is different for the two arrangements.
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.