Question

How does the (i) pole strength and (ii) magnetic moment of each part of a bar magnet change if it is cut into two equal pieces transverse to length?

Answer 1

When a bar magnet of magnetic moment ( \(\underset{M}\rightarrow\) = m₂ \(\underset{l}\rightarrow\)) is cut into two equal pieces transverse to its length,

(i) The pole strength remains unchanged (since pole strength depends on number of atoms in cross-sectional area).

(ii) The magnetic moment is reduced to half (since M ∝ length and here length is halved).