If an electron drops from the third orbit (n=3) to the first orbit (n=1) of H-atom, what will be the frequency and wavelength of the radiation emitted? What would have happened if the electron jumped from the first orbit to the third orbit?

Explanation

Let the frequency of the emitted radiation be v.
Then, `v=Rxxcxx[(1)/(n_(1)^(2))-(1)/(n_(2)^(2))]cps`
`=109677xx3xx10^(10)xx((1)/(1^(2))-(1)/(3^(2)))`
`=329031xx10^(10)xx(1-(1)/(9))`
[`becauseR=109677cm^(-1) and c=3xx10^(10)cm*s^(-1)`]
`=3.29xx10^(15)xx0.889=2.925xx10^(15)` cps
Wavelength of emitted radiation,
`lamda=(c)/(v)=(3xx10^(10))/(2.925xx10^(15))=1.025xx10^(-5)cm=1025` Å
When an electron jumps from the 1st orbit to the 3rd orbit then energy is absorbed. the frequency and wavelength of absorbed radiation is the same i.e, the frequency and wavelength of absorbed radiation will be `2.925xx10^(15)` cps and 1025 Å respectively.