An electron collides with a hydrogen atom in its ground state and excites it to the $n=3$ state. The energy given to the hydrogen atom in this inelastic collision (neglecting the recoil of the hydrogen atom) is (in $\text{ eV}$)

The four lowest energy levels of an $H$-atom are shown in the figure. The number of possible emission lines would be

What is the excited state of an atom?

$A$ $12.5 \ eV$ electron beam is used to bombard gaseous hydrogen at room temperature. It will emit:

$A$ 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 = $ . . . . . . .

The ground state energy of the hydrogen atom is $-13.6 \ eV$. The kinetic and potential energy of the electron in the second excited state are,respectively: