Two identical small conducting spheres are separated by 0.50m. Sphere A carries +5.0μC and sphere B carries −3.0μC. The spheres are touched together and then returned to their original positions. What is the magnitude and nature of the electrostatic force between them after they are separated? (Take k=8.99×109N⋅m2/C2.)
a) 3.6×10−2N, attractive
b) 3.6×10−2N, repulsive
c) 1.4×10−1N, repulsive
d) 1.8×10−2N, repulsive