What happens to the magnetic field of the coil on its axis at a point very very far away from its centre, if the radius of the coil is doubled keeping the current flowing through it unchanged?

Asked by Topperlearning User | 18th May, 2015, 03:37: PM

Expert Answer:

The magnetic field at a point on the axis of the coil is given by

If the point lies very very far away , then x>>a

Therefore,       ………………………..1

From Eq.1 if we double the radius (a) of the coil, the field becomes four times.

Answered by  | 18th May, 2015, 05:37: PM