A parallel-plate capacitor , made of two circular plates of radius R = 10 cm, is being charged. What is the magnitude of the induced magnetic field induced by the displacement current between the plates of the capacitor at a distance r = 2 cm from the axis of the plates at a time when the electric field varies at the rate dE/dt = 2 × 1012 V/m s?

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?