8D.1 Which of the following transitions are allowed in the electronic emission spectrum of an hydrogenic atom: (a) 2s 1s, (b) 2p → 1s, (c) 3d →2p, (d) 5d → 2s, (e) 5p → 3s, (f) 6f4p?

8d1.

Before solving the problem please also give a brief explanation of the concept or associated equation(s) and variables