Calculate the energy associated with the third orbit of $He^{+}$.

In $He^{+}$ ion,the energy of $2^{nd}$ orbit is $-13.6 \ eV/atom$. The kinetic energy of the same orbit for $He^{+}$ ion will be:

$A$ photon of wavelength $3000 \ \mathring{A}$ strikes a metal surface. The work function of the metal is $2.13 \ eV$. What is the kinetic energy of the emitted photoelectron (in $eV$)? $\left(h=6.626 \times 10^{-34} \ J \ s\right)$

The electron in the hydrogen atom undergoes a transition from higher orbitals to an orbital of radius $211.6 \text{ pm}$. This transition is associated with:

What is the hydrogen spectrum? Give its characteristics.

Calculate the energy required for the process $He_{(g)}^{+} \rightarrow He_{(g)}^{2+} + e^{-}$. The ionization energy for the $H$ atom in the ground state is $2.18 \times 10^{-18} \, J \, atom^{-1}$.