Question

Three small spheres each carrying a positive charge $q$ are placed on the circumference of a circle of radius $r$ to form an equilateral triangle. The electric field at the centre of the circle is :

• A. $\frac{3q}{r^2}$
• B. $\frac{3q}{r}$
• C. $\frac{q}{\sqrt{2}}-\left(\frac{q}{r^2}\right)$
• D. $zero$

Answer 1

The correct option is D $zero$

The electric field at the centre by
$E=\frac{kq}{r^2}$
The three electric fields are equal in magnitude and at ${120}^0$ to each other.
$\therefore$ The Net E at centre is zero