Question

Positive and negative point charges of equal magnitude are kept at $(0,0\frac{a}{2})$ and $(0,0\frac{-a}{2})$ respectively. The work done by the electric field when another positive point charge is moved from $(-a,0,0)$ to $(0,a,0)$ is :

• A. positive
• B. negative
• C. zero
• D. depends on the path connecting the initial and final positiions

Answer 1

Answer: (C)

zero

The charges make an electric dipole. $A$ and $B$ points lie on the equitorial plane of the dipole. Therefore potential at $A=$ potential at $B$
$W=Q(V_A-V_B)=q\times 0=0$