A point charge is initially at rest at point A

PHYSICS · Single correct · AP · Physics 2: Algebra-based · Electric Force Field and Potential · Electric Force Field and Potential

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}

(b)

-90\,\mu\text{J}

(c)

0\,\mu\text{J}

(d)

180\,\mu\text{J}