Two small silver spheres, each of mass m=8.6 g, are separated by distance d=1.3 m. As a result of transfer of some fraction of electrons from one sphere to the other, there is an attractive force F=620 kN between the spheres. Calculate the fraction of electrons transferred from one of the spheres. To evaluate the total number of electrons in a silver sphere, you will need to invoke Avogadro's number, the molar mass of silver equal to 107.87 g/mol and the fact that silver has 47 electrons per atom.