# Electric field bounded by two spherical shells

1. Apr 6, 2009

### sylvian

Greetings!

I have a question which I hope you would like to answer. I am on my last year of high school so please bear with me. I am planning to read Griffiths' book on electrodynamics, though, so that I can fully grasp my problem. This problem is not a homework question.

Let there be a radial electric field bounded by the shells of two concentric spheres of different radii.

These shells are not physical; they merely bound the electric field.

Let the space between the two shells always remain constant and let the magnitude of the electric field vary with respect to time. Also, let the radii of the shells vary with time whilst still having a constant space between them.

Let there be an observer far outside the shells. Will he detect any electromagnetic radiation?

Let the radius become very small, and by small I mean that the distance from the outer shell to the observer is much greater than the radius.

Will he still, if he detected any radiation before, detect any electromagnetic radiation?