Question

A, B, C are three points on a circle of radius $1cm$. These points form the corners of an equilateral triangle. A charge $2C$ is placed at the centre of the circle. The work done in carrying a charge of $0.1\mu C$ from A to B is :

• A. $Zero$
• B. $18\times {10}^{11}J$
• C. $1.8\times {10}^{11}J$
• D. $54\times {10}^{11}J$

Answer 1

The correct option is A $Zero$

Potential at a distance $1cm$ from centre is constant given by $\frac{kQ}{\left(1cm\right)}$
$\therefore$ The circle is equipotential surface
When a charge is moved from A to B
there is no change in potential
$\therefore W=q\Delta V,here\Delta V=0$
$\therefore W=0$