The figure shows the electric field lines around three-point charges A, B and C.

(i) Which charges are positive?

(ii) Which charge has the largest magnitude? Why?

(iii) In which region or regions of the picture could the electric field be zero? Justify your answer.

(a) Near A
(b) Near B
(c) Near C
(d) Nowhere

Hint: The electric field lines emanate from positive charges and enter into negative charges.
Step 1: Identify the charges.

(i) Here, in the figure, the electric lines of force emanating from A and C.  Therefore, charges A and C must be positive.

Step 2: The no. of field lines depends on the magnitude of the charge.

(ii) The number of electric lines of forces emanating is maximum for charge C here, so C must have the largest magnitude.

Step 3: The electric field is zero where the electric fields due to all the charges cancel out each other.

(iii) Point between two like charges where electrostatic force is zero is called neutral point. So, the neutral point lies between A and C only.

Now, the position of the neutral point depends on the strength of the forces of charges. Here, more electric lines of forces show higher strength of charge C than A. So the neutral point lies near A.