Question

two conducting spheres A and B of the same size are situated at some distance apart each has a charge of + q coulomb and they repel each other with a force of 10^-5Newton .Third conducting and charged spheres of same size is first touched with a and then with weak and then place exactly between A and B. calculate the resultant force on C​

Answer 1

Net force on sphere C = 0.75 x 10^-5 N

Explanation:

According to the Coulomb's law:

F = kq1q2 / r^2

Let the separation between the charges be r.

F = k q^2 / r^2 = 10^-5 N

Charge on sphere A = Charge on sphere C = q / 2

Total charge on C = q + q/2

Total charge on C = 1.5 q

Total charge on sphere c = total charge on sphere B = 1.5 q / 2 = 0.75 q

Force on sphere C = k ( 0.75 q ) (0.75 q ) / (r /2 )^2

Force on sphere C = 2.25 k q^2 / r^2 = 2.25 F

Net force on sphere C = 2.25 F - 1.5 F = 0.75 F

Thus net force on sphere C = 0.75 x 10^-5 N towards A.