two charges of 40 microc and -20 micro c are placed at a certain distance apart. they are touched and kept at the same distance.the ratio of their initial to the final force between them is

Answer 1

say they are d = 1

F = k (4)(-2)/1^2 = -8 k attracting

later each has average (4-2)/2 = 1
in other words 10 microc each but now they repel (same charge)
F = k (1)(1)/1^2 = k

-8/+1 = -8