A coil of area `100cm^(2)` having 500 turns carries a current of `1mA` . It is suspended in a uniform magnetic field of induction `10^(-3)wb//m^(2)` . Its plane makes an angle fo `60^(@)` with the lines of induction. The torque acting on the coil is

Explanation

Given`i=1mA=10^(3)=10^(-3)A,N=500,B=10^(-3)Wb//m^(2)`
`theta=60^(@) , tau=?A=100cm^(2)=100cm^(2)=100xx10^(-4)m^(2)`
Couple acting on the coil is given by `tau=BiAN sin phi`
Where `phi` is angle made by normal to the plane of coil with `B. phi=90-60=30^(@)`
`:. C=10^(-3)xx10^(-3)xx100xx10^(-4)xx500xxsin 30`
`=250xx10^(-8)Nm`