Current Attempt in Progress A positive point charge (q = +9.14 x 10-8 C) is surrounded by an equipotential surface A, which has a radius of rA = 1.78 m. A positive test charge (qo = +3.76 x 10-1 C) moves from surface A to another equipotential surface B, which has a radius rB. The work done by the electric force as the test charge moves from surface A to surface B is WAB = -7.06 x 10-9 J. Find rB. IB = iCurrent Attempt in Progress The drawing shows a set of equipotential surfaces seen in cross-sections. Each is labeled according to its electric potential. A 2.3 x 10-7 C point charge is placed at position A. Find the work done on the point charge by the electric force when it is moved (a) from A to B, and (b) A to C. B +650.0 V +150.0 V +550.0 V DI +250.0 V +450.0 V +350.0 V $2.0 cm (a) Number i Units (b) Number i Units