Question

What is Ritz combination principle\[?\]

Answer 1

Hint: First we know that the Ritz combination principle is the theory proposed by Walter Ritz in \[1908\]. It is used to describe the relationship of the spectral lines for all atoms. Lines of the spectra of elements could be predicted from existing lines.

Complete answer:
The Ritz combination Principle states that the spectral lines of any element include frequencies that are either the sum or the difference of the frequencies of two other lines.
 The energy (\[E\]) of a photon of light is proportional to the frequency (\[\nu \]) i.e., \[E \propto \nu \] \[ \Rightarrow E = h\nu \] ----(1)
Where, \[h\] is the Planck constant.
We know that the frequency of light (\[\nu \]) is proportional to the wave number or reciprocal wavelength (\[\lambda \]) i.e., \[\nu \propto \dfrac{1}{\lambda }\]
\[ \Rightarrow \]\[\nu = \dfrac{c}{\lambda }\] where \[c\] is the speed of light.
Then the equation (1) can be written as
\[E = \dfrac{{hc}}{\lambda }\]
Hence the ritz combination principle can also be expressed in terms of wavenumbers which are the sum or difference of wavenumbers of two other lines.

Additional information: A Spectra is a condition which exists when electromagnetic radiation passes through a prism it splits up and forms a collection of lines representing the different wavelengths. The spectra can be divided into two types, namely emission and absorption spectra.

Note:
The Ritz combination principle is obvious when we know that spectra are due to transitions between energy levels. An atom can decay from a higher state (state 2) to a ground state (state 0) either directly or in two steps. Energy (\[E = h\nu \]) is conserved, so the two frequencies of the latter route add to the frequency of the first route.