Fig shows the electric field lines around three points charges A,B,C.
(a) Which charges are positive ?
(b) Which charge has the largst magnitude ? Why ?
(c ) In which region or regions of the picture could be the electric field be zero? Justify your answer.
(i) near A, (ii) near B, (iii) near C, (iv) nowhere.

Explanation

(a) We can see that the electric field lines are originating from the charges A and C, therefore A and C must be positive charges.
(b) The number of electric field lines around charge C is the highest, hence the magnitude of the charge on C must be the largest.
(c) It is obvious that the charge B is negative and the charge C is positive and therefore the null point cannot exist in between the positive charge C and negative charge B. The null point exists between two similar charges , which are A and C in this case. The magnitude of the charge on A is smaller than C, hence the null point will be obtained near A .