Three point charges are fixed at the vertices of an equilateral triangle ABC of side…
PHYSICS · Multi-part · CBSE · Physics · Electrostatic Potential and Capacitance · Electrostatic Potential and Capacitance
Problem
Three point charges are fixed at the vertices of an equilateral triangle ABC of side 10cm placed in vacuum: +4μC at A, −4μC at B, and +4μC at C.
(i) Draw, on the plane of the triangle, a qualitative set of equipotential surfaces indicating at least three distinct potential values. Clearly mark the positions of the charges.
(ii) On your diagram locate two points P and Q such that ∣E∣P>∣E∣Q. Explain your choice on the basis of the density of the equipotential surfaces.
(iii) A 1nC test charge is moved slowly from P to Q along one of the equipotential surfaces you have sketched. Calculate the work done by the external agent.
(iv) Comment, with reasons based on the equipotential concept, on the sign (positive, negative or zero) of the work required to move the same test charge directly from vertex A to the midpoint of side BC.