Question

A, B, C are three points on a Circle of radius1 cm. These points from corners of an equilateral triangle A charge 2C is place at the center of the circle The work done carrying a charge of 0.1 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

Answer: (A)

Potential at a distance $1cm$ from centre is constant given by $\frac{kQ}{(1cm)}$
$\therefore$ 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 $\Delta V=0$
$\therefore W=0$