Question

A bar magnet of magnetic moment $80$ units is cut into two halves of equal length, the magnetic moment of each half will be 40 units.

• A. True
• B. False

Answer 1

The correct option is A True

Given,

Initial magnetic moment,$M=80$units

Final magnetic moment $=40$ units

Using $M=m\times l$

Where, m=pole strength, l= length

Final length$=\frac{l}{2}$

$⟹\frac{M^{{}^{\prime }}}{M}=\frac{m\times \frac{l}{2}}{m\times l}$

$⟹M^{{}^{\prime }}=\frac{1}{2}M=\frac{1}{2}\times 80=40$

Thus true.