Three equal point charges, each with charge 1.35?C , are placed at the vertices of an equilateral triangle whose sides are of length 0.350m . What is the electric potential energy U of the system? (Take as zero the potential energy of the three charges when they are infinitely far apart.)
Call the charges A, B and C. The total potential energy is the sum
of the potential energies of all pairs: A and B, A and C, B and C.
There are 3 pairs.
Since charges are equal and the distances between all charges are
equal, the total potential energy is 3 times the potential energy
of one pair of charges.
the potential energy of the system is 3 times energy needed to keep two 1.35*10^-6 C charges at 0.35m distance.
potential energy = 3 * k * (1.35*10^-6)^2 / 0.35 (K=8.987*10^9)
= 0.14039 J
Get Answers For Free
Most questions answered within 1 hours.