question_answer

Three charges, each + q, are placed at the comers of an isosceles triangle ABC of sides BE and AC, 2a. D and£ are the mid points of BE and CA. The work done in taking a charge Q from D to E is

A) \[\frac{eqQ}{8\pi {{\varepsilon }_{0}}a}\]            

B) \[\frac{qQ}{4\pi {{\varepsilon }_{0}}a}\]               

C)  zero                     

D) \[\frac{3qQ}{4\pi {{\varepsilon }_{0}}a}\]

Correct Answer: C

Solution :

Here, AC = BC \[{{V}_{D}}={{V}_{E}}=V\] \[V=Q[{{V}_{E}}-{{V}_{D}}]\] \[W=Q\,[V-V]\] \[W=0\]