The centers of two small metal spheres with a charge of 7.4 × 10−8 C are 10 cm from each other. a) What is the electric force between them? b) One of the spheres touches another identical neutral one, what is now the electric force if they are kept at the same distance? The constant in the Coulomb's law expression is k = 9.0 × 109 Nm2C2.