Question

A bar magnet of length $l$, pole strength $p$ and magnetic moment ${}^{\prime }{\overrightarrow{m}}^{\prime }$ is split $l/2$ into two equal pieces each of length. The magnetic moment and pole strength of each piece is respectively _______ and _____

• A. $\overrightarrow{m},p/2$
• B. $\frac{\overrightarrow{m}}{2},p/2$
• C. $\frac{\overrightarrow{m}}{2},p$
• D. $\overrightarrow{m},p$

Answer 1

The correct option is C $\frac{\overrightarrow{m}}{2},p$

On cutting a bar magnets in two pieces in this manner (i.e cutting perpendicular to its length), pole strength doesn't change.

New pole strength $=P$

New magnetic moment$=\frac{l}{2}=\frac{\overrightarrow{m}}{2}$

[In the question, symbol (standard symbol) used for magnetic pole strength and moment are exchanged and answer is given according to standard symbol]