In hydrogen atom, electron makes transition from $n = 4$ to $n = 1$ level. Recoil momentum of the $H$ atom will be

The characteristic spectrum of an element is produced when:

Which of the following transition in Balmer series for hydrogen atom will have longest wavelength

In a hydrogen atom, if $\lambda_B$ represents the wavelength of the last line of the Balmer series and $\lambda_L$ represents the wavelength of the last line of the Lyman series, then $\lambda_B$ is how many times $\lambda_L$?

If wavelength corresponding to 2nd line of Lyman series is $\lambda$, then the wavelength corresponding to last line of Balmer series will be

In Raman effect, Stoke’s lines are spectral lines having

If wavelength corresponding to 2nd line of Lyman series is $\lambda$, then the wavelength corresponding to last line of Balmer series will be

The wavelength of the energy emitted when electron comes from fourth orbit to second orbit in hydrogen is $20.397\,\,cm$. The wavelength of energy for the same transition in $H{e^ + }$ is

Hydrogen atom is excited from ground state to another state with principal quantum number equal to ${\rm{4}}$. Then the number of spectral lines in the emission spectra will be

The absorption transitions between the first and the fourth energy states of hydrogen atom are ${\rm{3}}$. The emission transitions between these states will be

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