Two small metal spheres are far from each other and are connected by a metal wire with a switch in the middle (all metal objects here are conductors).Initially the switch is open. Sphere 1, with radius 12 cm, is given a positive charge, 12C. Sphere 2, with radius 8.0 cm, is given a positive charge, 3.0C. Required:
What is the initial voltage of each sphere?

The electric field between square plates of a parallel-plate capacitor has magnitude e. the potential across the plates is maintained with constant voltage by a battery as they are pulled apart to twice their original separation, which is small compared to the dimensions of the plates. the magnitude of the electric field between the plates is now equal to a)e b)e/4 c)e/2 d)4e e)2e