Say we are looking at a positively charged rod with uniform charge density and a radius of R.(adsbygoogle = window.adsbygoogle || []).push({});

When using Gauss' law and taking a cylindrical surface we use the formula

E = lambda/2*pi*epsilon*r

When we derive this equation we are assuming R is significantly smaller than L and so we consider the charged body to be similiar to an rod that is co-axial to the Gaussian cylinder.

What if we want to consider what E is inside the cylinder at say r=R/2

I have read on another forum that we would consider the electric field inside the rod as 0 but that doesn't make sense because a charged rod with uniform charge density will have some electric field inside the rod as long as we are not right in the center where the field would cancel each other out.

If we do consider the EF inside the rod to be 0 then we must be assuming that the diifference between the magnitude of the EF caused from the opposite sides of the rod is insignificant but I do not see this assumption clarified anywhere.

Could someone please clarify this for me?

Thanks

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# Gauss' Law: Cylindrical Symmetry

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