A current-carrying circular loop lies on a smooth horizontal plane. Can a uniform magnetic field be set up in such a manner that the loop turns around it self (i.e. turns about the vertical axis).

Explanation

No, because that would require `tau` to tbe in the vertical direction. But `tau=I A xx B`, and since A of the horizontal loop is in the vertical direction, `tau` would be in the plane of the loop for any B.