Question

A magnet of mass 50 g has a magnetic moment of \( 4.2 \times 10^{-7} \, \text{A m}^2 \). The density of the magnet is 7.2 g/cm³. The intensity of magnetization in A/m is \(\underline{\hspace{2cm}}\) (round off to 3 decimal places).

Hint:

The intensity of magnetization is calculated by dividing the magnetic moment by the volume of the material.

Answer 1

Correct Answer: 0.058

The intensity of magnetization \( I_m \) is given by the formula:
\[ I_m = \frac{M}{V} \] Where:
- \( M = 4.2 \times 10^{-7} \, \text{A m}^2 \) is the magnetic moment,
- \( V \) is the volume of the magnet, and
- \( \rho = 7.2 \, \text{g/cm}^3 = 7200 \, \text{kg/m}^3 \) is the density of the magnet.
The volume \( V \) of the magnet is calculated as:
\[ V = \frac{m}{\rho} = \frac{0.05 \, \text{kg}}{7200 \, \text{kg/m}^3} = 6.94 \times 10^{-6} \, \text{m}^3 \] Now, substituting the values into the formula for \( I_m \):
\[ I_m = \frac{4.2 \times 10^{-7}}{6.94 \times 10^{-6}} \approx 0.058 \, \text{A/m} \] Thus, the intensity of magnetization is approximately \( 0.058 \, \text{A/m} \).