On a smooth inclined plane at `30^@` with the horizontal a thin current carrying metallic rod is placed parallel to the horizontal ground. The plane is located in a uniform magnetic field of `0*15tesla` in the vertical direction. For what value of current can the rod ramain stationary? The mass per unit length of rod is `0*30kgm^-1`.

Answer

`11*3A`

Explanation

In equilibrium position, figure.
`Bil cos theta=mg sin theta`
or `i=(mg sin theta)/(Bl cos theta)=(m/l)g/Btantheta`
`=(0*3xx9*8xxtan 30^@)/(0*15)=11*3A`