How much work must we do on an electron to move it from point A, which is at a potential of +50V, to point B, which is at a potential of -50 V, along the semicircular path shown in the figure? Assume the system is isolated from outside forces. (e = 1.60 × 10^-19C)

Question

Quizplus · Accepted Answer

The work done on an electron is given by the equation W = -qΔV, where q is the charge of the electron and ΔV is the change in potential. Since the electron is moving from a positive potential to a negative potential, the change in potential is ΔV = (-50 V) - (+50 V) = -100 V. Therefore, the work done on the electron is

W = -(1.60 × 10^-19 C)(-100 V) 
= 1.60 × 10^-17 J

The answer is therefore choice B.

How Much Work Must We Do on an Electron to Move