An electromagnetic mechanism for a safety gate uses a solenoid to pull an iron plunger against a spring to open the latch.
Explain why the plunger must be made of iron rather than brass.
When the solenoid is activated, a force of 3.60 N3.60\text{ N}3.60 N is applied to the spring, causing it to compress by 1.80 cm1.80\text{ cm}1.80 cm. Calculate the spring constant of the spring in N/m\text{N/m}N/m.
State two modifications to the solenoid or circuit that would increase the magnetic force on the plunger.
13 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.