According to Bohr's theory,the angular momentum of an electron in the $5^{th}$ orbit is: (in $, h/\pi$)

The Bohr radius of a hydrogen-like species is $70.53 \text{ pm}$. The species and the stationary state $(n)$ are respectively (Given: Hydrogen atom Bohr radius is $52.9 \text{ pm}$)

The angular momentum of the $2^{nd}$ Bohr orbit of the $H$ atom is $x$. Find the angular momentum of the $1^{st}$ excited state of $Li^{+2}$.

If the velocity of an electron in the $n^{th}$ orbit of a hydrogen atom is $0.0109 \times 10^{10} \, cm \, s^{-1}$,what is the value of $n$?

In which transition of the hydrogen atom will the emitted radiation have the lowest frequency?

The kinetic energy of an electron in the ground state of a $Be^{3+}$ ion is given by: