A certain charge distribution produces electric potential that varies along the X axis as shown in figure. [There is no field in y or z direction] (a) At which point (amongst A, B, C, D and E) does a negative charge feel the greatest force in positive X direction? (b) Find the upper limit of the speed that a proton can have, as it passes through the origin, and still remain bound near the origin. Mass and charge of a proton are m and e. How will your answer change for an electron?

Answer

(a). D
(b). `sqrt((2eV_(0))/(m))` Electron cannot remain bound for any speed.