# How does the strength of an object's electric field change with distance?

Jun 1, 2015

It depends on the source of the electric field.

For a point charge, it reduces as $\frac{1}{r} ^ 2$ , if r is the distance from the charge.

For a very long charged wire, it reduces as $\frac{1}{r}$.

But, for a very long thin sheet (charged), it is a constant i.e. it doesn't decrease with distance from the sheet.

Electric fields generated by changing magnetic fields again have different properties.

So, it is the source which makes the difference.