Question

A bar magnet of magnetic moment 5 Am² is placed in a uniform magnetic induction 3 x 10^-5 T. If each pole of a magnet experiences a force of 2.5 x 10^-4 N then the magnetic length of the magnet is ____________.

Options

• 0.2 m

• 0.8 m

• 0.6 m

• 0.4 m

Answer 1

A bar magnet of magnetic moment 5 Am² is placed in a uniform magnetic induction 3 x 10^-5 T. If each pole of a magnet experiences a force of 2.5 x 10^-4 N then the magnetic length of the magnet is 0.6 m.

Explanation:

F = mB where m is pole strength.

`therefore "m" = "F"/"B"`

`= (2.5 xx 10^-4)/(3 xx 10^-5)`

`= 25/3  "Am"`

Magnetic moment M = mL

`therefore "L" = "M"/"m"`

`= (5 xx 3)/25`

`= 0.6  "m"`