Question

There is a fixed positive charge $Q$ at $O$. $A$ and $B$ are points equidistant from $O$. A positive charge $+q$ is taken slowly by an external agent from $A$ to $B$ along $ACB$. Then,

• A. The total work done on the charge is zero.
  
• B. The work done by the electrostatic force from $A$ to $C$ is negative.
  
• C. The work done by the electrostatic force from $C$ to $B$ is positive.
  
• D. The work done by electrostatic force in taking the charge from $A$ to $B$ is dependent on the actual path.
  

Answer 1

Answer: (A), (B), (C)

The work done by the electrostatic force from $C$ to $B$ is positive.


Option $\left(A\right)$ is correct because the potentials of $A$ and $B$ are same as the points are equidistant from $O$. Therefore, there is no change in potential energy of the system. Thus, work done on the charge $=0$.

Option $\left(B\right)$ is correct because the charge is going from low potential to high potential.

Option $\left(C\right)$ is correct because the charge is going from high potential to low potential.

Option $\left(D\right)$ is incorrect because electrostatic force is a conservative force. Hence, work done is independent of path.