The field lines for two point charges shown in fig.

(i) Is the field uniform?
(ii) Determine the ratio `q_(A)//q_(B)`.
(iii) What are the sign of `q_(A)` and `q_(B)` ?
(iv) Apart from infinity, where is the neutral point?
(v) If `q_(A)` and `q_(B)`are separated by a distance `10(sqrt(2)-1)` cm, find the position of neutral point.
(vi) where will the lines meet which are coming from A and are not meeting at `q_(B)`?
(vii) Will a positive charge follow the line of force if free to move?

Explanation

(i) No
(ii) The number of lines coming from or coming to a charge is proportial to the magnitude of the charge, so
`(q_(A))/(q_(B))=12/6=2`
(iii) `q_(A)` is positive and `q_(B)` is negetive.
(iv) C is the other netual point.
(v) for neutral point
`E_(A)=E_(B)implies (1)/(4 pi epsilon_(0))(q_A)/((l+x)^(2))= (1)/(4 pi epsilon_(0))(q_(B))/(x^(2))`
or, `((l+x)/(x))^(2) =(q_(A))/(q_(B))=2` or `x=10cm`
(vi) at infinity .
(vii) No, As lines of force are curved, the direction of velocity and acceleration will be different. Hence, a charge cannot follow strictly the lines of force. Also to move on some curved path, centripetal force is required. whereas the lines of force will provide only tangential force.