Find the possible values of energy of a particle of mass m located in a spherically symmetrical potential well U (r) = 0 for r < ro and U(r) = ∞ for r = r0, in the case when the motion of the particle is described by a wave function ψ (r) depending only on r. When solving the Schr6dinger equation, make the substitution ψ (r) = χ (r)/r.