Paper 3 · electromagnetic induction
The north pole of a magnet is pulled out of a solenoid connected to a galvanometer. Points A, B, C and D lie on the wire, with the induced current flowing from B to A through the external circuit. Which points does the current flow between in the external circuit?
Model answer
B to A
Also accepted: from B to A, B and A
Explanation: Using Lenz's law to oppose the withdrawal of the north pole, the induced current flows from B to A through the external circuit (galvanometer).
Derived from ZIMSEC Physics Paper 3, June 2003, Q3