Question

Three charges are located at the vertices of an equilateral triangle as shown in the figure. 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)

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

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