Determine the electrostatic potential energy of a system consisting of two charges $7 \mu C$ and $-2

Question

Determine the electrostatic potential energy of a system consisting of two charges $7 \mu C$ and $-2 \mu C$ placed at $(-9	ext{ cm}, 0, 0)$ and $(9	ext{ cm}, 0, 0)$ respectively.

Professor PC Thomas Classes · Answer

Distance between charges $r = 9	ext{ cm} - (-9	ext{ cm}) = 18	ext{ cm} = 0.18	ext{ m}$. Potential energy $U = \frac{1}{4\pi\epsilon_0} \frac{q_1 q_2}{r} = 9 	imes 10^9 	imes \frac{7 	imes 10^{-6} 	imes (-2 	imes 10^{-6})}{0.18} = -0.7	ext{ J}$.