Question

Find the intensity of magnetization of a magnet with moment \( 4 \, \text{Am}^2 \) which weighs 50 grams. (Density of the material of a magnet = 5000 kg/m\(^3\))

• A. \( 10^5 \, \text{A/m} \)
• B. \( 3 \times 10^5 \, \text{A/m} \)
• C. \( 2 \times 10^5 \, \text{A/m} \)
• D. \( 4 \times 10^5 \, \text{A/m} \)

Hint:

The intensity of magnetization is given by the ratio of the magnetic moment to the volume of the material.

Answer 1

The Correct Option is D

Step 1: Formula for magnetization.
The magnetization \( I \) is related to the magnetic moment \( M \) and the volume \( V \) by: \[ I = \frac{M}{V} \] The volume \( V \) of the magnet is given by: \[ V = \frac{m}{\rho} \] where \( m \) is the mass of the magnet, and \( \rho \) is its density. Given that the mass is \( 50 \, \text{grams} = 0.05 \, \text{kg} \), and the density is \( 5000 \, \text{kg/m}^3 \), the volume is: \[ V = \frac{0.05}{5000} = 1 \times 10^{-5} \, \text{m}^3 \] Step 2: Calculate the intensity of magnetization.
The intensity of magnetization is then: \[ I = \frac{4 \, \text{Am}^2}{1 \times 10^{-5} \, \text{m}^3} = 4 \times 10^5 \, \text{A/m} \] Step 3: Conclusion.
Thus, the intensity of magnetization is \( 4 \times 10^5 \, \text{A/m} \), which corresponds to option (D).