Aparticle of mass m is placed in a three-dimensional rect- angular box with edge lengths 2l, l, and l. inside the box the potential energy is zero, and outside it is in nite; therefore, the wave function goes smoothly to zero at the sides of the box. calculate the energies and give the quan- tum numbers of the ground state and the rst ve excited states (or sets of states of equal energy) for the particle in the box.