Question

Three charges $2q, - q, - q$ are located at the vertices of an equilateral triangle. At the centre of the triangle

• A. The field is zero but potential is non-zero
• B. The field is non-zero but potential is zero
• C. Both field and potential are zero
• D. Both field and potential are non-zero

Answer 1

Answer: (B)

The field is non-zero but potential is zero

Answer 2

Obviously, from charge configuration, at the centre electric field is non-zero. Potential at the centre due to 2q charge$V_{2q} = \frac{2q}{r}$

and potential due to – q charge

$V_{- q} = - \frac{q}{r}$ (r = distance of centre point)

∴ Total potential $V = V_{2q} + V_{- q} + V_{- q} = 0$