Question

A bar magnet made of steel has a magnetic moment of 2.5 A-m² and a mass of 6.6 × 10³ kg. If the density of steel is 7.9 × 10³ kg/m³ the intensity of magnetization is
1. 8.3 × 10^-7 A/m
2. 3 A/m
3. 6.3 × 10^-7 A/m
4. 8.2 × 10⁶ A/m

Answer 1

Correct Answer - Option 2 : 3 A/m

Concept:

The intensity of magnetization is defined as the ratio of magnetic moment and volume of the bar.

\(I=\frac{Magnetic~moment}{Mass/Density}\)

Analysis:

Given:

Magnetic moment = 2.5 A-m²

Mass = 6.6 × 10³ kg

Density = 7.9 × 10³ kg/m³

 Volume = 6.6/7.9 = 0.8 m³

\(I = \frac{2.5}{0.8} = 3.125 ~ A/m\)