A hollow soft-iron cylinder of negligible thickness is placed with its axis parallel…
PHYSICS · Multi-part · A Level · Physics · Fields and their consequences · Fields and their consequences
Problem
A hollow soft-iron cylinder of negligible thickness is placed with its axis parallel to an external non-uniform magnetic field. A small compass needle is located at the centre of the cavity.
(i) Explain the term ‘magnetic shielding’ with reference to magnetic field lines.
(ii) Using the behaviour of field lines in and around magnetic materials, explain why the compass needle shows almost no deflection when the soft-iron cylinder is present.
(iii) Predict and explain the observation if the cylinder were made of brass instead of soft iron.