A conducting track is clamped to a stationary bench. A permanent magnet assembly is secured to a separate trolley that is not attached to the track or its clamp.
While a current flows in the track, the magnetic force on the magnet assembly is 0.40 N towards the right.
What magnetic force acts on the conducting track?
A 0.40 N magnetic force at right angles to the force on the magnet assembly.
No magnetic force, because the clamp balances the force on the conducting track.
A magnetic force towards the left, but its size cannot be found without the current.
A 0.40 N magnetic force towards the left, opposite to the force on the magnet assembly.
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.