Two copper spheres are currently 1.2 meters apart. one sphere has a charge of +2.2 × 10-4 c and the other has a charge of –8.9 × 10-4 c. what is the force between the charged spheres? is the force attractive or repulsive?

The nuclear potential that binds protons and neutrons in the nucleus of an atom is often approximated by a square well. imagine a proton conned in an innite square well of length 105 nm, a typical nuclear diameter. calculate the wavelength and energy associated with the photon that is emitted when the proton undergoes a transition from the rst excited state (n 2) to the ground state (n 1). in what region of the electromagnetic spectrum does this wavelength belong?