Which series of the hydrogen atom lie in the infrared region?

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........$\mathring{A}$

What is the wavelength of light for the least energetic photon emitted in the Lyman series of the hydrogen spectrum (in $\text{ nm}$)? (Take $hc = 1240 \text{ eV nm}$)

$A$ hydrogen atom is excited from the ground state to another state with a principal quantum number equal to $4$. The number of spectral lines in the emission spectra will be:

$A$ hydrogen atom is excited from the ground state to a state with principal quantum number $n = 4$. The number of spectral lines emitted in the emission spectrum is:

If the first line in the Lyman series has wavelength $\lambda$,then the first line in the Balmer series has the wavelength