Question

?2. Three point charges are arranged in a square as in the diagram below

.Find an expression for the electric potential at point A. Assume that V = 0 at infinity.

How much work is required to create this assembly of charges?

2 2 2

Answer 1

Electric potential V = kq/r

V = V1+V2 +V3

r1 = L , r2 = (L^2+L^2)^0.5 = 1.414L

r3 = L

q1 =+3Q, q2 = +Q, q3 = -2Q

k = 9*10^9 N.m^2/C^2

V = (k*3Q/L) +(k*Q/1.414L) +(K*-2Q/L)

V = (kQ/L) ((3) +(1/1.414))- (2))

V = 1.71 (kQ/L)

Work done equal to change in potential energy

U = kq1q2/r

U = (k3Q*Q/L) +(k*Q*-2Q/L)+(k*3Q*-2Q/1.414L)

U = (kQ^2/L)((3) -(2) - (3*2/1.414))

U = -3.24(kQ^2/L)