A monochromatic beam of light is absorbed by a collection of ground$-$state hydrogen atoms in such a way that three different wavelengths are observed when the hydrogen relaxes back to the ground state.

$($a$)$ What is the wavelength of the incident beam?

An electron in an excited state can make a transition to a lower state by emission of a photon of the appropriate wavelength. $nm$

$($b$)$ What is the longest wavelength in the emission spectrum of these atoms?

$nm$

$($c$)$ To what portion of the electromagnetic spectrum does it belong?

$($d$)$ To what series does it belong?

$($e$)$ What is the shortest wavelength?

nm