A particle of mass m is confined to the surface of a sphere of radius R, but is otherwise free. It is put in the normalized state:
ψ(θ,φ) = (A, 0<θ<(π)/(2), 0<φ<(π)/(2)), (0, otherwise).
(a) Determine A.
(b) Find the probability of measuring the square of its angular momentum to be 2ℏ^(2).
(c) A small perturbation of the form H' = η cosθ sinφ is applied. How does this perturbation cause the l=1 energy level to split? Give energy corrections to lowest order in perturbation theory, and find the linear combinations of unperturbed states for which the perturbation is diagonal.