A magnetic dipole is under the effect of two magnetic field inclined at `75^(@)` to each other one of the fields has a magnitude of `1.5xx10^(-2)` t the magnets come to stable at an angle of 30 degrees with the direction of the field. the magnitude of othe field is

Options

A. `(15)/(2sqrt(2))xx10^(-2)T`
B. `(15)/sqrt(2)xx10^(-2)` T
C. `1.5xxsqrt(2)xx10^(-2)` T
D. `1.5 xx10^(-2)` T

Answer

B

Explanation

`B_(1)=1.5 xx10^(2)T`
`B_(2)=?`
In equilibrium position
`tau_(1)=tau_(2)`
`MB_(1) sin theta_(1)=MB_(2) sin theta_(2)`
`1.5 xx10^(-21) xxsin30^(@)=B_(2)xxsin 45^(@)`