Question

A bar magnet of magnetic moment ‘M’ is cut into two halves of equal length. What will be the magnetic moment of each half?

• A. $M$
• B. $\frac{M}{2}$
• C. $\frac{M}{4}$
• D. $\frac{M}{3}$

Answer 1

The correct option is B

$\frac{M}{2}$

Step 1: Given data

The magnetic moment of the bar magnet = M

Magnet is cut into two equal halves

Step 2: Finding the magnetic moment

We know,

For a bar magnet

$Magneticmoment=polestrength\times lengthofthemagnet$

1. When the magnet is cut into two equal halves then the length of the magnet becomes half.
2. From the above equation, we can say that if the length of the magnet becomes half then the magnetic moment also becomes half.

So, the new magnetic moment = $\frac{M}{2}$

Hence the correct option is (B) $\frac{M}{2}$