When an electron revolves in a stationary orbit,then:

If the wavelength of the first line of the Balmer series is $656.1 \ nm$,then the wavelength of the second line of this series will be ............. $nm$.

The emission spectrum of hydrogen is found to satisfy the expression for the energy change $\Delta E$ (in joules) such that $\Delta E = 2.18 \times 10^{-18} \left( \frac{1}{n_1^2} - \frac{1}{n_2^2} \right) \, J$ where $n_1 = 1, 2, 3 \dots$ and $n_2 = 2, 3, 4 \dots$. The spectral lines correspond to the Paschen series when:

$A$ quantum will have more energy if :

When a hydrogen atom (ionization energy $13.6 \ eV$) jumps from the third excited state to the first excited state,the energy of the emitted photon in this process is .............. $eV$.

Which of the following electronic transitions in a hydrogen atom will require the highest energy?