_____n=4
_____n=3
_____n=2
_____n=1
The wavelength of the light released when an electron jumps from higher energy state (n2) to lower energy state (n1) is λ1=R(n121−n221), here, λ is wavelength, R is Rydberg Constant.
When transition is from second excited state to first excited state,
n=3→n=2
λ01=R(221−321)...(1)
When transition is from third excited state to second orbit
n=4→n=2
(x20λ0)1=R(221−421)...(2)
Dividing (2)by(1)
⇒20x=221−321221−421=41−9141−161=365163=2027
⇒x=27