Acopper wire is 1.6 m long and its diameter is 1.1 mm. if the wire hangs vertically, how much weight (in n) must be added to its free end in order to stretch it 2.8 mm?

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?