Consider a circular loop in the Y - Z Plane with its centre at the origin O.
Let R be the radius of the loop and I is the steady current through the loop in anti-clock wise direction.
Consider a point P on the axis of the loop coinciding with X-axis at a distance x from O.
The magnitude of magnetic field at P due to current element dl is given by,
The element \(d\vec l\) is in Y - Z plane. Unit vector is in the x - y plane, Hence sin90°= 1
The direction of dB is perpendicular to the plane formed by \(d\vec l\) and \(\vec r\) Resolving dB into two components.
