two loops of wire of radii 1cm and 2cm resp.are placed coaxialy .current i passes through both in same direction initialyand then the the direction of current is reversed . what is the ratio of magnetic induction at centre in first and second case
two loops of wire of radii 1cm and 2cm resp.are placed coaxialy .current i passes through both in same direction initialyand then the the direction of current is reversed . what is the ratio of magnetic induction at centre in first and second case