The ionisation potential of a hydrogen atom is $-13.6 \ eV$. What will be the energy of the atom corresponding to $n = 2$?

Energy and radius of the first Bohr orbit of $He^{+}$ and $Li^{2+}$ are: $[$Given $R_{H} = 2.18 \times 10^{-18} \ J, a_{0} = 52.9 \ pm$ $]$

Rutherford's $\alpha$-particle scattering experiment concluded that:

The energy of a photon is $3 \times 10^{-12} \ erg$. What is its wavelength in $nm$? $(h = 6.62 \times 10^{-27} \ erg \cdot s; \ c = 3 \times 10^{10} \ cm/s)$

The maximum energy is present in any electron at

What is the shortest wavelength for the Paschen series of the $Li^{2+}$ ion?