An electron in the ground state of hydrogen was excited to a higher energy level using monochromatic radiations of wave length (lambda )975 Å . The longest wave length that appears in the resulting spectrum is due to transition from:

An electron in the ground state of hydrogen was excited to a higher en

1.	An electron in the ground state of hydrogen was excited to a higher energy level using monochromatic radiations of wave length (lambda )975 Å . The longest wave length that appears in the resulting spectrum is due to transition from:
Answer» `n_(4) to n_(1)` `n_(4) to n_(3)` `n_(5) to n_(4)` `n_(5) to n_(1)` Solution :The energy assoicated with radiation of WAVE length `975 Å`is given by `E = (12400)/(975)eV = 12.72 eV` [For a radiaton of WAVELENGHT x `Å` we know `E = (12400)/(x) eV`] `E = 13.6 [(1)/(n_(1)^(2)) - (1)/(n_(2)^(2))]eV` ` or12.72 = 13.6 [1 - (1)/(n_(2)^(2))] ""[becauseE = 12.72 eV]` or ` (1)/(n_(2)^(2))k = (13.6-12.72)/(13.6) = (0.88)/(13.6) = (1)/(16)` or `n_(2)^(2) = 16 , n_(2) ~= 4` The transition `n_(4) to n_(3)`willgivethe longestwave lenght.