The distance between the poles of a horse shoe magnet is 0.1 m and its pole strength is 0.01 amp-m. The induction of magnetic field at a point midway between the poles will be

Options

A. `2xx10^(-5)`T
B. `4xx10^(-6)`T
C. `8xx10^(-7)`T
D. Zero

Answer

3

Explanation

Net magnetic field at mid point `P, B=B_(N) +B_(S)`
where `B_(N)`=magnetic field due to N- pole
`B_(S) `= magnetic field due to S- pol e `B_(N)=B_(S)=mu_(0)/4pi m/r^(2)=10^(7)xx0.01/(0.1/2)^(2)=4xx10^(-7)`T
`:.B_(net)=8xx10^(-7)`T