Question

The emission spectrum of hydrogen discovered first and the region of the electromagnetic spectrum in which it belongs, respectively are:
a.Lyman, ultraviolet
b.Lyman, visible
c.Balmer, ultraviolet
d.Balmer, visible

Answer 1

Hint: In this problem , we have to say which of the following options is correct for the given statement. The emission spectrum of atomic hydrogen has been divided into several spectral series like Balmer series, Lyman series, Paschen series, Pfund series and Brackett series with wavelengths given by the Rydberg formula. It is based on the electron transition between the two energy levels.

Complete step by step answer:
Now we will discuss the given statement in details:
The first emission spectrum of a hydrogen atom is the Balmer series which was discovered by scientist Johann Balmer in 1885.
When the electron jumps from the outer orbit or the higher energy orbit to the second orbit ($n = 2$), the spectral lines formed are the Balmer series. The wavelength lies in the visible region
The wavenumbers of spectral lines present in the visible region of the hydrogen spectrum was shown by Johann Balmer in 1885 for the first time and the wavenumbers are given by: -
\[\dfrac{1}{\lambda } = R\left( {\dfrac{1}{{n_1^2}} - \dfrac{1}{{n_2^2}}} \right)\] , $\lambda $ is the wavelength.
where R is the Rydberg constant and its value is 109678 \[c{m^{ - 1}}\]
For the Balmer series: - \[{n_1}\] is 2 and \[{n_2}\] is 3, 4, 5 etc.
After discussing in detail we conclude that the Balmer spectrum which is the visible region is the first discovered emission spectrum of hydrogen.

So, the correct answer is Option d.

Additional information:
The series present in the hydrogen spectrum are the Lyman series which is in the ultraviolet region, Balmer series which is in the visible region, Paschen, Brackett, and Pfund series which is in the infrared region.

Note: The splitting of polychromatic light into constituent radiations is called dispersion and the pattern of radiation obtained due to dispersion is called a spectrum. There are two types of spectra.
Emission spectra- It is the pattern of bright lines or bands seen when electromagnetic radiation emitted by a substance is passed into a spectrometer. An emission spectrum is the characteristics of an emitting substance.
Absorption spectra- When an electromagnetic radiation is passed through an absorbing medium then a characteristic pattern of dark lines or bands are attained, that is termed as absorption spectra.