A regular polygon of n sides is formed by bending a wire of total length `2 pi r` which carries a
Channel: Doubtnut
Date: 2020-07-05

A regular polygon of n sides is formed by bending a wire of total length `2 pi r` which carries a current i. (a) Find the magnetic field B at the centre of the polygon. (b) By letting `n rarr oo` , deduce the expression for the magnetic field at the centre of a circular current.