A straight conductor and a magnetic field are both horizontal and at right angles to each other. The magnet producing the field rests on a top-pan balance. When current flows, the magnetic force on the magnet acts vertically downwards and the balance reading increases. The force on the magnet is equal in size to the force on the conductor. Use g=10 N/kgg = 10\ \mathrm{N/kg}g=10 N/kg.
The measurements are shown in the table.
| Measurement | Value |
|---|---|
| Increase in balance reading | 1.2 g |
| Current in the conductor | 2.0 A |
| Length of conductor in the field | 6.0 cm |
Calculate the magnetic flux density of the field.
86 exam-style questions on Edexcel GCSE Physics 12.3 The motor effect, covering 12.3.1 The motor effect, 12.3.2 Fleming's left-hand rule, 12.3.3 Force on a conductor, and 12.3.4 Electric motors. Each one has a worked solution and a mark scheme showing where the marks go.