Question

A charge of magnitude +2q is fixed at the origin. A second charge, −q, is fixed at a distance d away from the origin on the positive x axis.

a. Find the point(s) where the electric potential is zero?
b. How many points have an electric potential of zero?
c. How many points have an electric field of zero?

Answer 1

Step-by-step explanation:

(a) Let us assume that the potential at point x is equal to zero.

Then,

`k (2q)/(x) - (k(-d))/((d - x))` = 0

`(2)/(x) + (1)/((d- x))` = 0

`(2)/(x) = (-1)/((d-x))`

2d - 2x = -x

-x + 2x = 2d

or, x = 2d

Therefore, at a point x = 2d the electric potential is equal to zero.

(b) There will be only one point where an electric potential is zero and that point is x = 2d.

(c) Let us assume that
`E_(A)` and
`E_(B)` are electric fluids because of the charge +2q and -q respectively.

So, there is only one point where the charge can be zero and that point is D.