A current-carrying metal bar is used to move a shutter in a ventilation system. A technician tests the bar. In every test, the bar is perpendicular to a uniform magnetic field.
| Test | Magnetic flux density / T\text{T}T | Current / A\text{A}A | Length in field / cm\text{cm}cm | Force / N\text{N}N |
|---|---|---|---|---|
| A | 0.20 | 1.5 | 8.0 | 0.024 |
| B | 0.30 | 2.0 | 4.0 | 0.024 |
| C | 0.25 | 1.0 | 8.0 | 0.020 |
| D | 0.25 | 2.5 | 8.0 | 0.050 |
A student uses tests A and B to conclude that increasing the current does not increase the force.
Evaluate the student's conclusion using all the data.
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.