Two charges 2 C and 6 C are separated by a finite distance. If a charge of-4 C is added to each of them,the initial force of `12 xx 10^(3)` N will change to

Options

A. `4 xx 10^(3)` (repulsion)
B. `4 xx 10^(2)` (repulsion)
C. `6 xx 10^(3)` (attraction)
D. `4 xx 10^(3)` (attraction)

Answer

(d)

Explanation

Initial force b/w the charges ,
`F_(1) = Kq_(1)q_(2)/r^(2) = K(2)(6)/r^(2) = K12/r^(2)`
Final Force,
`F_(2) = K(2 - 4)(6 - 4)/r^(2) = - 4K/r^(2)`
`F_(1)/F_(2) = 12/-4`
`:. F_(2) = -4 xx 10^(3)`N