Six different charge distributions are shown in the figure w

Six different charge distributions are shown in the figure, with each object located at the corner of an equilateral triangle. Rank the six distributions in terms of their electric potential energy. Use >, <, and = signs to indicate your ranking.

Please tell me why.

Six different charge distributions are shown in the figure, with each object located at the corner of an equilateral triangle. Ran Use >,

Solution

potential energy of system of charges q1,q2,q3 located at corners of equilateral triangle

PE = k [(q1*q2)+(q2*q3)+(q3*q1)]/r

where k = 8.98*10^9 Nm^2/C^2 and r is distance between charges

SO we RANK energies by comparing value of S= [(q1*q2)+(q2*q3)+(q3*q1)]

A) S = [-4 -2 +2] = -4

B) S = [-2-2+1] = -3

C) S =[-16 -20 +20] = -16

D) S = [+6+3+2] = +11

E) S = [+3 -1-3] = -1

F) S = [+3 +18 +6] = +27

SO RANK IS F > D > E>B>A>C