(a) The enegy levels of an atom are as shown below. Which of them will result in the transition of a photon of wavelength 275 nm ?

(b) Which transition corresponds to emission of radiation of maximum wavelength ?

Explanation

Here, `lambda = 275 nm = 275 xx 10^(-9) m`
Therefore, energy of the emitting photon,
`E = (hc)/(lambda) = (6.62 xx 10^(-34) xx 3 xx 10^(8))/(275 xx 10^(-9))`
`= 7.22 xx 10^(-19) J = (7.22 xx 10^(-19))/(1.6 xx 10^(-19)) = 4.5 e V`
The photon of energy `4.5 e V` ("or of wavelength 275 nm")` will be emitted , corresponding to the transition `B`.