The net charge on an atom is equal to the overall difference between the number of protons in the nucleus versus the number of electrons around the nucleus, where a negative sign represents less protons and a positive sign represents more protons (than electrons).
<em>Hope</em><em> </em><em>this</em><em> </em><em>will</em><em> </em><em>help</em><em> </em><em>u</em><em>.</em><em>.</em><em>:</em><em>)</em>
Explanation:
It is given that,
Frequency of the laser light, 
Time,
(a) Let
is the wavelength of this light. It can be calculated as :



or

(b) Let n is the number of the wavelengths in one pulse. It can be calculated as :


n = 13440
Hence, this is the required solution.
It is called absorption spectrum because a gas of hydrogen will make a line spectrum and if viewed for another angle it would be between a continuum light and a emission line spectrum