2. (10 pt) Let ❘l, m) represent angular momentum states with integer l and the radial quantum number omitted.
(a) Show that (l, m'|z|l, m) = 0, (l, m'|pz|l, m) = 0 by using the parity-selection rule.
(b) Show that (l+2, m'|z|l, m) = 0, (l+2, m'|pz|l, m) = 0 by using the parity-selection rule.
(Note: recall that you made the same conclusions in the previous homework with the Wigner-Eckart theorem.)
(c) Show that (l + 1, m'|z2|l, m) = 0, (1+1, m'|p2|l, m) = 0, (1+1, m'|{z, p.}|l, m) = 0 by using the parity-selection
rule.