A bar magnet made of steel has a magnetic moment of `2.5 A m^2` and mass of `6.6 xx 10^(-5) kg`. If the density of steel is `7.9 xx 10^3 kg m^(-3)`, find the intensity of magnetization of the magnet.

Options

A. `1.0 xx 10^(6) Am`
B. `4.0 xx 10^(6) Am`
C. `3.0 xx10^(6) Am`
D. `8.0 xx 10^(6)Am`

Answer

B

Explanation

`x=2.1xx10^(-5)`
Increase in magnetic held =`B-B_(0)`
`=B_(0)+B_(1)-B_(0)`
`B_(1)`
Now
% increase in magnetic field =`(B_(1))/(B_(0))xx100`
`=(mu_(0)I)/(mu_(0)H)xx100`
`(I)/(H)xx100`
`x xx 100`
`2.1xx10^(-5)xx100`
`=2.1xx10^(-3)`