Question

A bar magnet of magnetic moment 10 Am² has a cross sectional area of 2.5 × 10⁻⁴ m². If the intensity of magnetisation of magnet is 10⁶ A/m, the losgth oft bar magnet is ______.

Options

• 2 cm

• 4 cm

• 6 cm

• 8 cm

Answer 1

A bar magnet of magnetic moment 10 Am² has a cross sectional area of 2.5 × 10⁻⁴ m². If the intensity of magnetisation of magnet is 10⁶ A/m, the losgth oft bar magnet is 4 cm.

Explanation:

Given: Magnetic moment (M) = 10 Am²

Area of cross-section (A) = 2.5 × 10⁻⁴ m²

Intensity of magnetisation (I) = 10⁶ A/m

By using the formula for the magnetic moment:

M = I × A × L

L = `M/(I A)`

= `10/((10^6) (2.5 xx 10^-4))`

= `10/250`

= 0.04 m

= 4 cm