A student drops a strong magnet through a long vertical coil of wire. The two ends of the coil are connected to each other through a switch.
In Test 1, the switch is open.
In Test 2, the switch is closed.
The magnet takes longer to fall through the coil in Test 2 than in Test 1.
Explain why a potential difference is induced across the ends of the coil in both tests.
Explain why the magnet falls more slowly through the coil in Test 2.
The student repeats Test 2 with a coil that has more turns.
Predict how the time taken for the magnet to fall through the coil changes. Explain your answer.
48 exam-style questions on OCR GCSE Physics 4.2 Uses of magnetism, covering 4.2.1 The motor effect, 4.2.2 Fleming's left-hand rule, 4.2.3 The force on a current-carrying conductor, 4.2.4 The electric motor, 4.2.5 Electromagnetic induction, 4.2.6 Alternators and dynamos, 4.2.7 How transformers work, 4.2.8 Transformer turns ratio, 4.2.9 Potential differences and turns in transformers, and 4.2.10 Microphones, loudspeakers and headphones. Each one has a worked solution and a mark scheme showing where the marks go.