Question

Two equipotential surfaces surround a +2.90 x 10-8-C point charge. How far is the 220-V surface from the 85.0-V surface?

Answer 1

The potential difference is
\[ V=220-85=135. \]
Now the potential V at distance d from a point charge Q is
\[ V=\frac{Q}{4\pi\epsilon_0 d} \]
If you solve this for d and plug in the potential difference and the charge you have your answer.

Answer 2

im lost there but ill try any other info would of coarse be handy if you could

Answer 3

can you tell me what e0 is

Answer 4

It's the permittivity of vacuum, a physical constant. It's value is
\[ \epsilon_0≈8.854188*10^{-12} \]
It has units farads per meter.