A positive point charge +Q?is located at x?= ?a.

(a) How much work is required to bring a second equal positive point charge +Q?from infinity to x?= +a?

(b) With the two equal positive point charges at x?= ?a?and x?= +a, how much work is required to bring a third charge ?Q?from infinity to the origin?

(c) How much work is required to move the charge ?Q from the origin to the point x = 2a along the semicircular path shown (Figure)?

2a