A sealed power-distribution unit contains a hidden straight conductor carrying a large constant current. The conductor passes at right angles through a flat inspection panel.
An engineer marks a point X on the panel. A probe measures the magnetic flux density and the direction of the magnetic field at positions around X. All the field directions shown are in the plane of the panel.
| Position relative to X | Distance from X | Magnetic flux density / μT\mu\text{T}μT | Field direction |
|---|---|---|---|
| north | 2.0 cm | 760 | west |
| east | 2.0 cm | 750 | north |
| south | 2.0 cm | 770 | east |
| west | 2.0 cm | 760 | south |
| north | 4.0 cm | 380 | west |
| east | 4.0 cm | 370 | north |
| south | 4.0 cm | 390 | east |
| west | 4.0 cm | 380 | south |
Use the results to explain why the conductor is likely to pass through the panel at X.
The direction of the current in the conductor is reversed, but the size of the current is unchanged. Describe how the results would change.
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.