Ampere's law provides us an easy way to calculate the magnetic field due to a symmetrical
Channel: Doubtnut
Date: 2020-07-26

Ampere's law provides us an easy way to calculate the magnetic field due to a symmetrical distribution of current. Its mathemfield expression is `ointvecB.dl=mu_0I_("in")`.  The quantity on the left hand side is known as line as integral of magnetic field over a closed Ampere's loop.  If the current density in a linear conductor of radius a varies with r according to relation `J=kr^2`, where k is a constant and r is the distance of a point from the axis of conductor, find the magnetic field induction at a point distance r from the axis when rlta. Assume relative permeability of the conductor to be unity.