Answer:
1.718 N , attractive
Step-by-step explanation:
r = 0.66 m, n = 5.7 x 10^13
q1 = 5.7 x 10^13 x 1.6 x 10^-19 = 9.12 x 10^-6 C
q2 = - 5.7 x 10^13 x 1.6 x 10^-19 = - 9.12 x 10^-6 C
F = K q1 q2 / r^2
F = 9 x 10^9 x 9.12 x 10^-6 x 9.12 x 10^-6 / (0.66)^2
F = 1.718 N
As both the charges are opposite in nature, so the force between them is attractive.