The ratio of the speed of the electrons in the ground state of hydrogen to the speed of light in vacuum is

The speed of an electron in the orbit of a hydrogen atom in the ground state is

An electron in a hydrogen atom,after absorbing energy photons,can jump between energy states $n_1$ and $n_2$ $(n_2 > n_1)$. It then returns to the ground state,emitting six different wavelengths in the emission spectrum. The energy of the emitted photons can be equal to,less than,or greater than the absorbed photon energy. Determine $n_1$ and $n_2$.

The energy required to excite an electron from the $1^{st}$ to the $3^{rd}$ Bohr orbit in $Li^{++}$ is ...... $eV$.

The magnetic moment of an electron due to its orbital motion is proportional to $(n =$ principal quantum number$)$

The energy of a hydrogen atom in the ground state is $-13.6 \, eV$. The energy of the $He^+$ ion in the first excited state will be .... $eV$.