In the shown figure a conducting ring of mass = 2kg and radius R = 0.5 m. lies on a smooth horizontal plane with its plane vertical. The ring carries a current of `I = (1)/(pi)A`. A horizontal uniform magnetic field of B = 12T is switched on at t =0. The initial angular acceleration `alpha` in `rad//sec^(2)` of the ring will be 4x if x is :

Answer

3

Explanation

`tau_("y-axis") = = I_("y-axis") rArr (I.pi r^(2))B=1//2mr^(2)alpha`
`alpha =12 rad//sec^(2) :. X =3`