Question

Two point charges of +2microcoulomb and +6microcoulomb repel each other with a force of 12n. if each is given as additional charge of -4microcoulomb . what will be the new force​

Answer 1

Answer: -4N

Explanation: You can use the formula,

F=Kq1q2/r^2

=> 12=9×10^9×2×10^-6×6×10-6/r^2

From here we get the value of r^2=9×10^-3

Now, after adding a charge of 4 micro coulomb each, new charges becomes -2uC and 2uC, so again using the formula, we get the value of F' = -4N