Two point charges `10 muC and -10 muC` are separated by a distance of 40 cm in air.
Calculate the electrostatic potential energy of the system, assuming the zero of the potential energy to be at infinity.

Explanation

Here `q_1 = + 10 muC =10 xx 10^(-6)C, q_2 = 10 muC = - 10 xx 10^(6) C and r = 40 cm= 0.4 m`
`:.` Potential energy of the system
`u = (q_1 q_2)/(4pi epsi_0r) = (9 xx 10^9 xx (10 xx 10^(-6)) xx (-10 xx 10^(-6)))/0.4 = -2.25 J`.