The pole strength of a 12 cm long bar magnet is 2.0 A-m. The magnetic induction at a point 10 cm away from the centre of the magnet on the axial line is `((mu_(0))/(4pi)=10^(-7)Hm^(-1))`

Options

A. `1.1xx10^(-4) T`
B. `2.2xx10^(3) T`
C. `1.1xx10^(-2) T`
D. `2.2xx10^(-2) T`

Answer

A

Explanation

Magnetic field on axial line, `B=(mu_(0))/(4pi)(2Md)/(d^(2)-l^(2))^(2)`
`impliesB=(mu_(0))/(4pi)(2xx(ml)xxd)/((d^(2)-l^(2))^(2))`
`impliesB=[(4pixx10^(-7))/(4pi)((2)xx(2)(0.12)(0.1))/([(0.1)^(2)-(0.6)^(2)]]]`
`impliesB=(48xx10)/(4096xx10^(-8))`
`therefore B=1.1xx10^(-4)T`