Hydrogen atoms are excited by a laser to the =4 state and then allowed to emit. what is the maximum number of distinct emission spectral lines (lines of different wavelengths) that can be observed from this system?

so total 6 spectral lines are possible here

Explanation:

Since the electron is at excited state of n= 4

so here we have electron from nth excited to lower possible state

here the lower most energy state is ground state

so we will have

here we know

n = 4

so total 6 spectral lines are possible here

overcharge is the right answer system