A bar magnet has length 4 cm , cross-sectional area $2 \mathrm{~cm}^2$ and magnetic moment $6 \mathrm{Am}^2$…

A bar magnet has length 4 cm , cross-sectional area $2 \mathrm{~cm}^2$ and magnetic moment $6 \mathrm{Am}^2$. The intensity of magnetisation of bar magnet is
  1. $9 \times 10^5 \mathrm{~A} / \mathrm{m}$
  2. $7.5 \times 10^5 \mathrm{~A} / \mathrm{m}$
  3. $4.5 \times 10^5 \mathrm{~A} / \mathrm{m}$
  4. $3.0 \times 10^5 \mathrm{~A} / \mathrm{m}$

Solution

Intensity of magnetization $\begin{aligned} & =\frac{M_{\text {net }}}{\text { Volume }} \\ & =\frac{M_{\text {net }}}{\text { length } \times \text { area of cross-section }} \\ & =\frac{6}{\left(4 \times 10^{-2}\right) \times\left(2 \times 10^{-4}\right)}=7.5 \times 10^5 \mathrm{~A} / \mathrm{m} \end{aligned}$

Asked in: MHT CET 2024 (11 May Shift 1)

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