The total energy of an electron in an atom in an orbit is $-3.4 \; eV$. Its kinetic and potential energies are,respectively:

In an inelastic collision, an electron excites a hydrogen atom from its ground state to an $M$-shell state. $A$ second electron collides instantaneously with the excited hydrogen atom in the $M$-state and ionizes it. At least how much energy must the second electron transfer to the atom in the $M$-state?

Energy levels $A, B$ and $C$ of a certain atom correspond to increasing values of energy, i.e., $E_A < E_B < E_C$. If $\lambda_1, \lambda_2$ and $\lambda_3$ are the wavelengths of radiations corresponding to transitions $C$ to $B, B$ to $A$ and $C$ to $A$ respectively, which of the following relations is correct?

What is the ratio of the total energy of an electron in a hydrogen atom in the first excited state to that in the third excited state?

If the ionization energy of a hydrogen atom in the ground state is $13.6 \ eV$,find the ionization potential of the third orbit in $eV$.

The binding energy of an electron in a $H$-atom with $n = 4$ is ....... $eV$. (Magnitude only)