As the $n$ (number of orbit) increases,the difference of energy between the consecutive energy levels

In the hydrogen atom spectrum, let $E_1$ and $E_2$ be the energies for the transitions $n=2 \rightarrow n=1$ and $n=3 \rightarrow n=2$ respectively. The ratio $E_2 / E_1$ is

If energy of $15 \ eV$ is given to an electron in the $4^{th}$ orbit,find its final energy when it comes out of the $H$-atom. (in $eV$)

The figure shows the energy levels of a certain atom. When the electron de-excites from $3E$ to $E$,an electromagnetic wave of wavelength $\lambda$ is emitted. What is the wavelength of the electromagnetic wave emitted when the electron de-excites from $\frac{5E}{3}$ to $E$?

$A$ hydrogen atom makes a transition from $n = 2$ to $n = 1$ and emits a photon. This photon strikes a doubly ionized lithium atom $(Z = 3)$ in an excited state and completely removes the orbiting electron. The least quantum number for the excited state of the ion for this process is:

The figure indicates the energy level diagram of an atom and the origin of six spectral lines in emission (e.g.,line no. $5$ arises from the transition from level $B$ to $A$). Which of the following spectral lines will also occur in the absorption spectrum?