Chapter 21: Q2Q (page 897)

In chapter 15 we calculated the electric field at a location on the axis of a uniformly charged ring. Without doing all those calculations explain why we can’t use Gauss law to determine the electric field at that location.

Short Answer

Expert verified

The electric field at the location on the axis of uniformly charged ring because field lines are not always perpendicular to the enclosed area for that location on the axis of ring.

Step by step solution

Conceptual Explanation

The Gauss law is used to find the electric field inside an enclosed surface by equating net flux inside the enclosed surface to net charge divided by permeability of free space.

Necessary condition to apply Gauss Law

The Gauss law can be only applicable for the surfaces in which the electric field lines are always perpendicular to the surface area. This condition is fulfilled only in symmetrical objects like sphere, cylinder etc.

Reason for avoiding the use of Gauss law to find the electric filed at a location on the axis of uniformly charged ring

The electric field lines from the uniformly charged ring are not always perpendicular to the enclosed area in which the location to find electric filed lies so Gauss Law is not applicable to find electric field at location on the axis of the uniformly charged ring.

Therefore, the electric field at the location on the axis of uniformly charged ring because field lines are not always perpendicular to the enclosed area for that location on the axis of ring.