Physics Question on electrostatic potential and capacitance

Question

There is $10$ units of charge at the centre of circle of radius $1\, m$ . The work done in moving $1$ unit of charge once around the circle is :

Answer 1

Solution

Here charge at centre $=10$ units, radius of circle $(r)=10\, m$ and charge moved around circle $=1$ unit, we know that when the charge is at the centre of a circle, the circumference will be equipotential, so work done in moving a charge around the circle is zero.