# Where is the voltage potential zero given two points?

1. Jul 1, 2009

### xcmntgeek

1. The problem statement, all variables and given/known data
Two charges are fixed in place with a separation d. One charge is positive and has ten times (n = 10) the magnitude of the other charge, which is negative. The positive charge lies to the left of the negative charge, as in Figure 19.10. Relative to the negative charge, locate the two spots on the line through the charges where the total potential is zero relative to d.
Positive distance to the left of -q: ____ X d
Positive distance to the right of -q: _____ X d

2. Relevant equations

V= kq/r

3. The attempt at a solution

0= k10q/(d-xd)+k-q/xd

That's about all I know, I'm sure we'll end up with a quadratic because there will be two spots where the potential = 0.
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Jul 1, 2009

### rock.freak667

Shouldn't this equation be

$$\frac{k 10q}{d-x} + \frac{-qk}{x}=0$$

I didn't really draw out the problem as I haven't done these questions in a few years.