Three point charges

PHYSICS · Multi-part · CBSE · Physics · Electrostatic Potential and Capacitance · Electrostatic Potential and Capacitance

Problem

Three point charges

q

q

and

-2q

are kept at the vertices

A

B

and

C

respectively of an equilateral triangle of side

\ell

placed in vacuum. (i) Derive an expression for the electric potential at the centroid of the triangle in terms of

q

\ell

and the electrostatic constant

k

. (ii) For what value of

q

(in terms of

\ell

and fundamental constants) will the potential at the centroid become zero? (iii) If

q = 5\,\mu\text{C}

and

\ell = 0.10\,\text{m}

, compute the total electric potential energy of the system of three charges.