Electrons in a sample of H-atoms make transition from state n=x to some lower excited state. The emission spectrum from the sample is found to contain only the line belonging to a particular series. If one of the photons has an energy of 0.6375 eV . Find the value of x.
`["Take" 0.6375 eV = 3/4 xx0.85 eV]`

Answer

8

Explanation

Energy of the photon`=0.6375 eV=3/4xx0.85 eV=3/4xx13.6/4^(2)=13.6/4^(2)(1-1/4)=13.6(1/4^(2)-1/8^(2))`
Thus, this photon coresponds to transition `n=8` to `n=4` (Brakett series)
`:. X=8` Ans.