The energy of the second Bohr orbit of the hydrogen atom is $-328 \ kJ \ mol^{-1}$. Hence,the energy of the fourth Bohr orbit would be .............. $kJ \ mol^{-1}$.

How did Niels Bohr obtain detailed information regarding the structure of atoms and molecules?

The angular momentum of an electron in a given orbit is $J$. Its kinetic energy will be:

The wavelength of the first line of the Lyman series for hydrogen is $1216 \ \mathring{A}$. The wavelength of the first line of the same series for a $10$ times ionized sodium atom $(Z = 11)$ will be ......... $\mathring{A}$.

In the hydrogen spectrum,if an electron transitions from the $6^{th}$ orbit to the $3^{rd}$ orbit,what is the total number of spectral lines produced?

$A$ 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 $eV$)? $\left(h=6.626 \times 10^{-34} \ J \ s\right)$