A wire bent in the shape of a regular n-polygonal loop carries a steady current I. Let `l` be the perpendicular distance of a given segment and R be the distance of vertex both from the centre of the loop. The magnitude of the magnetic field at the centre of the loop is given by -

Options

A. `(n mu_(0) I)/(2pi l) "sin " (pi//n)`
B. `(n mu_(0) )/(2pi) (I)/( R) ""sin (pi //n)`
C. `(n mu_(0))/(2pi) (I)/(l) ""cos (pi//n)`
D. `(nmu_(0) I)/(2pi R) ""cos (pi //n)`

Answer

A

Explanation

`B = (mu_(0) I)/(4pi l) xx 2 sin theta " "` [ where `2 theta = (2pi)/(n)`]