Imagine a light bulb. You want to collect all the light coming from it so you wrap it in solar panels. It doesn't matter how far the solar panels are away from the light bulb or how large the spherical shell of solar panels is, as long as it's fully enclosing the light bulb all the light will be collected.

Same idea. You are adding up all the electric flux coming from a source. So it doesn't matter how far away you are from the source, as long as you fully enclose it in an imaginary shell you will capture all the flux. Just like light intensity, the flux density will decrease as you get farther away because it spreads out but when you are farther away the surface enclosing the source is also a much larger area too and you still end up collecting the same amount of light/flux except now you are collecting it over a larger area witih lower density rather than a smaller area with higher density. So density might change, but the total does not.

Originally Posted by shermaine

When calculating the electric field, why is it the distance is not been a issue?

I've got a post up about the electric field for a sheet. If there are small sheets in resistors that there might be a different formula for, then I should probably clarify that I am interested in an equation for a sheet that is about two feet by two feet. Have you heard any information about fields for this type of sheet between two point electric contacts? I'd be really interested in a specific formula for E, and knowing if the equation is different for different sheets or different properties of sheets.

By the way, how are you calculating the field? Is it from an experiment or equations? If equations, what are the equations involving?