Take the 2-minute tour ×
Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It's 100% free, no registration required.

There is a sphere with radius $R$ that carries a polarization $$\vec P(\vec{r})=k\vec r$$

$\vec r$ is the vector from the center.

I found electric field the outside generated by the sphere is $\vec E=0$

Can you, please, explain it in physical terms?

share|improve this question
add comment

1 Answer

up vote 0 down vote accepted

Your polarized sphere is spherically symmetric. Therefore outside the sphere, in the vaccuum, the solution must be spherically symmetric. However, the only spherically symmetric solution of Maxwell's Equations in vacuum is the electric field of a point charge. Since your sphere has zero net charge, it must be the electric field of a point with zero charge. Thus $\vec{E} = 0$.

share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.