$A$ 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:

What is the wavelength of the least energetic photon emitted in the Lyman series of the hydrogen atom spectrum? (in $nm$)

For a hydrogen atom,$\lambda_1$ and $\lambda_2$ are the wavelengths corresponding to the transitions $1$ and $2$ respectively,as shown in the figure. The ratio of $\lambda_1$ and $\lambda_2$ is $\frac{x}{32}$. The value of $x$ is:

Find the maximum wavelength of the Brackett series for a hydrogen atom in $\mathring A$.

What is the shortest wavelength present in the Paschen series of spectral lines (in $;nm$)?

When the electron in a hydrogen atom jumps from the fourth Bohr orbit to the second Bohr orbit,one gets the: