Physics

Problem

3.0\,\mu\text{C}

point charge is initially at rest at point A, where the electric potential is

40\,\text{V}

. The charge is released and accelerates freely to point B, where the potential is

10\,\text{V}

. Immediately upon arrival at B, an external agent applies a force that moves the charge slowly to point C, where the potential is again

40\,\text{V}

, bringing the charge to rest at C. What is the total work done by the external agent over the entire trip from A to C? a)

90\,\mu\text{J}

-90\,\mu\text{J}

0\,\mu\text{J}

180\,\mu\text{J}