How does electric field intensity vary with distance from a small charged particle?

Question

What causes some equipotential lines near a conductor to be parallel?

and why is it that in electrostatics conductors are assumed to have infinite conductivity?

Answer 1

1. 1/r^2

2. Parallel equipotentials means parallel field lines. This is the case for the field in the vicinity of a large flat charged plate.

3. For electrostatic considerations, the fact that the electrons can move at all is sufficient. So it doesn't matter what the conductivity is as long as it isn't zero.