how many sublevels exist in the fourth principle energy level?

Question

a) 2
b) 4
c) 16
d) an infinite number

Answer 1

l may be 0, 1, 2, 3, 4, etc to a maximum of n-1. Therefore, for n = 4 it can be no larger than 3.
So the four sublevels will be 0, 1, 2, and 3.