Question

There is $10$ units of charge at the centre of a circle of radius $10m$. The work done in moving one unit of charge around the circle once is

• A. $0$
• B. $10$ units
• C. $100$ units
• D. $1$ unit

Answer 1

Answer: (A)

$0$

Work done is zero because the direction of movement of charge and direction of force are perpendicular to each other.
work= $F.r.\cos \left(\theta \right)$
so if the angle is ${90}^o$ then work done$=0$