The wavelength of the photon emitted by a hydrogen atom when an electron makes a transition from $n = 2$ to $n = 1$ state is ...... $nm.$

In a hydrogen atom spectrum,when an electron jumps from the second excited state to the first excited state,the wavelength of radiation emitted is $\lambda$. If the electron jumps from the third excited state to the second orbit,the wavelength of radiation emitted will be $20 \lambda / x$. The value of $x$ is

If the wavelength of the first line of the Balmer series of hydrogen is $6561 \; \mathring{A}$,the wavelength of the second line of the series should be........$\mathring{A}$

The frequencies for the series limit of the Balmer and Paschen series are $f_1$ and $f_3$,respectively. If the frequency of the first line of the Balmer series is $f_2$,then the relation between $f_1, f_2$,and $f_3$ is:

The electron in a hydrogen atom in a sample is in the $n^{th}$ excited state. The number of different spectral lines obtained in its emission spectrum will be:

If $\lambda_1$ is the wavelength of the series limit of the Lyman series,$\lambda_2$ is the wavelength of the first line of the Lyman series,and $\lambda_3$ is the series limit of the Balmer series,then the relation between $\lambda_1, \lambda_2,$ and $\lambda_3$ is: