How Does Electric Field Behave Inside a Uniformly Charged Sphere?

AI Thread Summary
Inside a uniformly charged sphere, the electric field (E) behaves in a way that initially seems counterintuitive. As one moves toward the center, the charge enclosed decreases, which suggests E should decrease, while the proximity to the charge suggests E should increase. However, calculations show that the decrease in charge density, which decreases by a factor of r^3, dominates over the increase due to proximity, leading to a net decrease in E. The final conclusion is that the electric field decreases linearly as the radius (r) decreases. This analysis aligns with Gauss's law and provides a satisfactory understanding of the electric field behavior within the sphere.
theowne
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Under the Gauss' law section of the book.

Homework Statement


As you penetrate a uniform sphere of charge, E should decrease as less charge is inside the sphere, while E should increase because you are closer to the center of this charge. Which effect dominates?


Homework Equations


εΦ = q


The Attempt at a Solution



This is what I was thinking, maybe I'm completely misguided. q = charge density * 4/3 pi r^3 so q decreases by a factor of r^3. From gauss law' E = q / ε 4 pi r^2. So E decreases with q which decreases by r^3 while E increases with r^2 factor due to the denominator. So I would guess that q is the dominant factor there. Would it be a saisfactory answer if I just did [charge density * 4/3 pi r^2] / [ε 4 pi r^2] = (charge density * r) / (3 ε) = E so in the end as r decreases the E field will decrease.
 
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Looks great to me! E decreases linearly as r decreases.
 
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