Question

The vertices of an equilateral triangle lie on the circumference of a circle of radius $6cm$. Charges each of $3C$ are placed at the vertices. If a charge of $1C$ is placed at the center of the circle, the force acting on it is:

• A. $0.75\times {10}^{13}N$
• B. $1.5\times {10}^{13}N$
• C. $2.25\times {10}^{13}N$
• D. $Zero$

Answer 1

The correct option is D $Zero$

The electric field at the center due to each 3C will be $KQ/r^2$ directed away from the charge at the center.

since all the 3 electric fields of equal magnitude inclined at ${120}^o$ and so the results of any two electric fields cancel the third electric field and thus the resultant electric field at the center of the circle becomes zero.

Hence force on 1C becomes zero