Which spectral series of the hydrogen atom is found in the ultraviolet region?

The spectral series of the hydrogen atom that lies in the visible region of the electromagnetic spectrum is:

The wavelength of radiation emitted is $\lambda_0$ when an electron jumps from the second excited state to the first excited state of a hydrogen atom. If the electron jumps from the third excited state to the second orbit of the hydrogen atom,the wavelength of the radiation emitted will be $\frac{20}{x} \lambda_0$. The value of $x$ is

In the spectrum of hydrogen,the ratio of the longest wavelength in the Lyman series to the longest wavelength in the Balmer 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:

The ratio of the longest to the shortest wavelength emitted in the Paschen series of a hydrogen atom is: