The ionisation energy of $Li^{2+}$ is equal to

The ionization energy of hydrogen is $13.6 \, eV$. If $h = 6.6 \times 10^{-34} \, J \cdot s$,the order of magnitude of the Rydberg constant $R$ will be:

The de-Broglie wavelength associated with an electron of a hydrogen atom in its ground state is (in $\text{ Å}$)

The total energy of an electron $E_n = -\frac{Z^2me^4}{8\epsilon_0^2n^2h^2}$ in an atom is based on which hypothesis? Under what condition is this formula true?

In a hydrogen-like ion,the energy difference between the $2^{\text{nd}}$ excitation state and the ground state is $108.8 \ eV$. The atomic number of the ion is:

Mention the value of the Rydberg constant with its unit.