Two point charges M and N having charges +q and -q respectively are placed at a distance apart. Force acting between them is F . If 30 % of charge of N is transferred to M , then the force between the charges becomes:

Step-by-step solution

Initial force: F = kq^2 r^2 30% of charge of N transferred to M: Charge transferred = 0.3q New charge on M = +q + (-0.3q) = 0.7q New charge on N = -q - (-0.3q) = -0.7q F' = k(0.7q)(0.7q) r^2 = 0.49 kq^2 r^2 = 49 100 F