Suppose a force does 50 J of work on a system. At the same time, 50 J of heat leaves the system. What is the change in the internal energy of the
system? *
A. +100 J
B.+50J
C. -50 J
DOJ

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?