(a) In hydrogen atom an electron undergoes transitions from 2nd excited state to the 1st excited state and then to the ground state. Identify the spectral series to which transition belong .
(b) Find out the ratio of the wavelenght of the emitted radiations in the two cases.

Explanation

(a) When an electron undergoes a transition from 2nd excited state (n = 3) to the 1st excited state (n = 2) in hydrogen atom, first spectral line of Balmer series is emitted.
When the electron jumps from Ist excited state in 2) to the ground state (1=1), first spectral line of Lyman series is emitted.
(b) `(1)/(lambda_(1)) = R [(1)/((2)^(2)) - (1)/((3)^(2))] = (5R)/(36) and (1)/(lambda_(2)) = R [(1)/((1)^(2)) - (1)/((2)^(2))] = (3R)/(4)`
`rArr (lambda_(1))/(lambda_(2)) = (27)/(5) = 5.4`