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 energy required to excite an electron from the first orbit to the third orbit in a hydrogen atom is .......... $eV$.

Energy levels $A, B, C$ of a certain atom correspond to increasing values of energy, $i.e.,$ $E_A < E_B < E_C$. If $\lambda_1, \lambda_2$ and $\lambda_3$ are the wavelengths of radiations corresponding to the transitions $C$ to $B$, $B$ to $A$ and $C$ to $A$ respectively, which of the following statements is correct?

If an electron falls from $n = 3$ to $n = 2$,then the emitted energy is $..........$ $eV$.

The wavelength of a spectral line emitted by a hydrogen atom in the Lyman series is $\frac{16}{15 R} \ cm$. What is the value of $n_2$? $(R = \text{Rydberg constant})$

The wave number of the first emission line in the Balmer series of $H$ atom spectrum is ($R =$ Rydberg constant).