Point Charges?

Question

Two point charges are placed on the x axis. The charge +2q is at x = 1.5 m, and the charge -q is at x = -1.5 m.

(a) There is a point on the x axis between the two charges where the electric potential is zero. Where is this point?
x =.... m

(b) The electric potential also vanishes in one of the following regions. Identify the appropriate region.
1. Region 1: 5.0 m > x > 1.5 m
2. Region 2: -1.5 m > x > -3.0 m
3. Region 3: -3.5 m > x > -5.0 m

(c) Find the value of x referred to in part (b).
x = ........m

Answer 1

V=kQ/r
At null point, V1+V2=0

a. -0.5 m
2k/(1.5+0.5) + -1k/(1.5-0.5) = 0

b. Region 3.

c. -4.5 m
2k/(1.5+4.5) + -1k/(4.5-1.5) = 0