A bar magnet has a length of 8cm. The magnetic field at a point at a distnace 3cm from the centre in the broadside-on position is found to be `4 xx 10^(-6) T`. Find the pole strength of the magnet.

Options

A. `6xx10^(-5)Am`
B. `5xx10^(-5)Am`
C. `2xx10^(-4)Am`
D. `3xx10^(-4)Am`

Answer

a

Explanation

(a) Magnetic field due to a bar magnet in the broad-side on position is given by
`B=(mu_(0))/(4pi)(M)/([r^(2)+(l^(2))/(4)]^(3//2)) , M=ml`
After substituting the values and simplifying we get
`B=6xx10^(-5)A-m`