A rectangular bar of ferromagnetic material is placed in a uniform external magnetic…
PHYSICS · Multi-part · CBSE · Physics · Magnetism and Matter · Magnetism and Matter
Problem
A rectangular bar of ferromagnetic material is placed in a uniform external magnetic field that is then switched off after several seconds. Subsequently, the bar is observed to behave as a weak bar magnet even though no current now flows in the region.
Answer the following.
(1) Describe, on a microscopic scale, the sequence of events taking place inside the ferromagnetic bar while the external field is present.
(2) After the external field is removed, the bar retains a measurable magnetic field. Explain why the alignment of magnetic domains persists in some ferromagnetic materials but not in others, making reference to internal structure and energy considerations.