The $Bohr$ model of an atom could not account for:

The potential energy of an electron in the hydrogen atom is $-6.8 \ eV$. Indicate in which excited state the electron is present.

The ratio of the maximum wavelengths of the Lyman and Balmer series is ....

Given the energy equation $E_n = -313.6/n^2$,if $E_n = -34.84$,which of the following could be the value of $n$?

The work function for a caesium atom is $1.9 \, eV$. Calculate $(a)$ the threshold wavelength and $(b)$ the threshold frequency of the radiation. If the caesium element is irradiated with a wavelength of $500 \, nm$,calculate the kinetic energy and the velocity of the ejected photoelectron.

The radius ratio of Bohr's first orbit of hydrogen-like species $He^{+}$,$Li^{2+}$,and $Be^{3+}$ is: