12. Two copper spheres, A and B, have initial charge 10 MC and 5.0 ,uC respectively and radii 'I'A = 2.0 cm and r3 = 3.0 cm. The spheres are connected by a. conducting wire allowing charge to transfer before coming to equilibrium. How many electrons transfer from sphere A to sphere B? (1) 2.5 x 1013 (2) 5.6 x 1013 (3) 1.9 x 1013 (4) 0.63 x 1013 (5) 1.6 x 1013