The diagram shows the energy levels for an electron in a certain atom. Which transition shown represents the emission of a photon with the most energy?

In a hydrogen-like atom,an electron makes a transition from an energy level with principal quantum number $n$ to another with principal quantum number $(n - 1)$. If $n >> 1$,the frequency of the emitted radiation is proportional to:

How much work must be done to pull apart the electron and the proton that make up the Hydrogen atom,if the atom is initially in the state with $n = 2$?

If the ionisation energy for the hydrogen atom is $13.6$ eV, then the energy required to excite it from the ground state to the next higher state is nearly (in $eV$)

The energy of an electron in the $n^{th}$ orbit of a hydrogen atom is given by $E_n = -\frac{13.6}{n^2} \, eV$. How much energy in $eV$ is required to move an electron from the $n = 2$ orbit to the $n = 3$ orbit?

$A$ hydrogen atom is bombarded with electrons accelerated through a potential difference of $V$, which causes excitation of hydrogen atoms. If the experiment is performed at $T = 0 \,K$, the minimum potential difference needed to observe any Balmer series lines in the emission spectra will be $\frac{\alpha}{10} \,V$, where $\alpha = $ . . . . . . .