Question

A bar magnet has length 3 cm, cross-sectional area 2 cm³ and magnetic moment 3 Am². The intensity of magnetisation of bar magnet is ______.

Options

• 2 × 10⁵ A/m 

• 3 × 10⁵ A/m

• 4 × 10⁵ A/m

• 5 × 10⁵ A/m

Answer 1

A bar magnet has length 3 cm, cross-sectional area 2 cm³ and magnetic moment 3 Am². The intensity of magnetisation of bar magnet is 5 × 10⁵ A/m.

Explanation:

From question, L = 3 cm = 3 × 10^-2 m

A = 2 cm² = 2 × 10⁴ m²

M = 3 Am²

Intensity of magnetisation, Im = `"M"/("L"xx"A")`

= `(3"A"//"m"^2)/(3xx2xx10^-6"m"^3)`

= `1/2xx10^6` A/m

= 5 × 10⁵ A/m