There are 3 charges of +1C, +2C and +3C at the vertices of an equilateral triangle of length 2m. What is the Potential energy of the system assuming potential energy at infinite separation to be zero?
The answer is simply the sum of potential energy between all pairs of particles.
P.E = kq1q2/r12 + kq2q3/r23 + kq3q1/r31
P.E=k2(2×3+3×1+1×2)P.E=9×109×112P.E=4.95×1010J