Electron in hydrogen atom first jumps from third excited state to second excited state and then from second excited to the first excited state. The ratio of the wavelengths `lambda_(1), lambda_(2)` emitted in the two cases is

Options

A. `7//5`
B. `27//20`
C. `27//5`
D. `20//7`

Answer

D

Explanation

`E_(1)=(hc)/(lambda_(1))=13.6 [(1)/((3)^(2))-(1)/((4)^(2))] ........(i)`
`E_(2)=(hc)/(lambda_(2))=13.6 [(1)/((2)^(2))-(1)/((3)^(2))] ......(ii)`
dividing eq. (ii) by eq. (i)
`lambda_1/lambda_(2)=(1/4-1/9)/(1/9-1/(16))=(20)/7`