Question

A permanent magnet in the shape of a thin cylinder of length $50$cm has intensity of magnetisation ${10}^{6}A{m}^{-1}$. The magnetisation current is

• A. $5\times {10}^5$ A
• B. $6\times {10}^5$ A
• C. $5\times {10}^4$ A
• D. $6\times {10}^4$ A

Answer 1

The correct option is A $5\times {10}^5$ A

Here, $l=50cm=0.5m,M={10}^{6}A{m}^{-1}$
As$M=\frac{MagnetisationCurrent\left(I_M\right)}{l\left(length\right)}$
Then, $I_M=M\times l={10}^6\times 0.5=5\times {10}^{5}A$.