1. Four identical point charges are arranged at the corners of a square. The electric field E and potential V at the center of the square are
(a) E = 0, V = 0.
(b) E = 0, V ≠ 0.
(c) E ≠ 0, V ≠ 0.
(d) E ≠ 0, V = 0.
(e) E = V regardless of the value.
2. If it takes an amount of work W to move two + q point charges from infinity to a distance d apart from each other, then how much work should it take to move three + q point charges from infinity to a distance d apart from each other?
(a) 2W.
(b) 3W.
(c) 4W.
(d) 6W.