What are the frequency and wavelength of a photon emitted during a transition from n = 5 state to the n = 2 state in the hydrogen atom?

Explanation

Since `n_(1) =5 nad n_(f)=2`, this transition gives rise to a spectral line in the visible region of the Balmer series.
`Delta E=2.18xx10^(-18)J[(1)/(5^(2))-(1)/(2^(2))]`
`=-4.58xx10^(-19)J`
It is an emission energy The frequency of the photon (taking energy in terms of magnitude ) is given by
`v=(DeltaE)/(h)=(4.58xx10^(-19)J)/(6.626xx10^(-34)Js)=6.91xx10^(14)"Hz"`
`lamda=(c)/(v)=(3.0xx10^(8)"ms"^(-1))/(6.91xx10^(14)"Hz")=434nm`