The shortest wavelength of the spectral line in the Brackett series is .......

The transition from the state $n = 4$ to $n = 3$ in a hydrogen-like atom results in ultraviolet radiation. Infrared radiation will be obtained in the transition from:

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

The electron in a hydrogen atom is initially in the third excited state. When it finally moves to the ground state,the maximum number of spectral lines emitted is:

The ratio of wavelengths of the second line in the Balmer series and the first line in the Lyman series of a hydrogen atom is:

If an electron in a hydrogen atom jumps from an orbit of level $n=3$ to an orbit of level $n=2$,the emitted radiation has a frequency ($R=$ Rydberg constant,$C=$ velocity of light).