Question

An iron bar of length l has magnetic moment М. It is bent at the middle of its length such that the two arms make an angle 60° with each other. The magnetic moment of this new magnet is ______.

Options

• 2 M

• `M/sqrt 3`

• M

• `M/2`

Answer 1

An iron bar of length l has magnetic moment М. It is bent at the middle of its length such that the two arms make an angle 60° with each other. The magnetic moment of this new magnet is `bbunderline(M/2)`.

Explanation:

When the rod is bent in the middle,

l_eff = `2 xx l/2 sin 30^circ`

= `l/2`

So,

M' = `m xx l/2`

= `M/2`