The pole strength of each pole of a short bar magnet having magnetic length 2 cm and the magnetic field produced by this magnet at a point 20 cm from the centre of the magnet on the line making an angle of `60^(@)` with the axis is `3.75 xx10^(-5) Wb//m^(2)`,is

Options

A. 213.4 Am
B. 103.4 Am
C. 111.4 Am
D. 113.4Am

Answer

D

Explanation

`B=(mu_(0))/(4pi)(M)/(r^(3))sqrt(3cos^(2)60+1)`
`3.75xx10^(-5)=(10^(-7)xx2xx10^(-2)xxm)/(8xx10^(-3))sqrt(3cos^(2)60+1)`
`m=113.4Am`