What will be the angular momentum of an electron,if the energy of this electron in an $H$-atom is $-1.5 \, eV$ (in $J \cdot s$)?

The wavelengths of the spectral lines in the spectrum of deuterium $(_{1}H^{2})$ differ slightly from those in the spectrum of hydrogen $(_{1}H^{1})$ because ...

Assume that there is no repulsive force between the electrons in an atom,but the force between positive and negative charges is given by Coulomb's law as usual. Under such circumstances,calculate the ground state energy of a $He$ atom.

In a hydrogen atom,the electron is moving around the nucleus with a velocity of $2.18 \times 10^{6} \; m/s$ in an orbit of radius $0.528 \; \mathring{A}$. The acceleration of the electron is:

According to the classical electromagnetic theory,calculate the initial frequency of the light emitted by the electron revolving around a proton in a hydrogen atom.

$A$ light of energy $12.75 \; eV$ is incident on a hydrogen atom in its ground state. The atom absorbs the radiation and reaches to one of its excited states. The angular momentum of the atom in the excited state is $\frac{x}{\pi} \times 10^{-17} \; eVs$. The value of $x$ is $........$ (use $h=4.14 \times 10^{-15} \; eVs$)