Q. Three charges $2q, - q, - q$are located at the vertices of an equilateral triangle. At the circumcentre of the triangle
A) The field is zero but potential is non-zero
B) Potential is zero and the field is infinity
C) Both the field and potential are zero
D) The field is non-zero but potential is zero
Explanation
(d) Potential due to charge $–q\ at\ A\ $
$V_{A} = \frac{1}{4\pi\varepsilon_{0}k}\frac{- q}{\left( r^{2} \right)^{1/2}}$
Potential due to charge $–q\ at\ B$
$V_{B} = \frac{1}{4\pi\varepsilon_{0}k}\frac{- q}{\left( r^{2} \right)^{1/2}}$
Potential due to charge $–q\ at\ C$
$V_{C} = \frac{1}{4\pi\varepsilon_{0}k}\frac{- q}{\left( r^{2} \right)^{1/2}}$
Total potential at centre.
$V = V_{A} + V_{B} + V_{C}$
$V = 0$
From charge configuration at the centre electric field in non zero.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.