Question

Three equal point charges, each with charge 1.05 μC , are placed at the vertices of an equilateral triangle whose sides are of length 0.300 m . 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.)

Use ϵ0 = 8.85×10⁻¹² C²/N⋅m2 for the permittivity of free space.

Answer in J

Answer 1

Q = Charge at each vertices of triangle = 1.05 x 10^-6 C

a = length of side of equilateral triangle = 0.3 m

U = electric potential energy of the system

Electric potential energy of the system is given as

U = Q Q/(4a) + Q Q/(4a) + Q Q/(4a)

U = 3 Q²/(4a)

U = 3 (1.05 x 10^-6)² /(4 x 3.14 x 8.85 10^-12x 0.3)

U = 9.92 x 10^-2 J