According to Bohr's theory,the angular momentum of an electron revolving in the second orbit of a hydrogen atom will be:

The radius of an electron's second stationary orbit in Bohr's atom is $R$. The radius of the $3rd$ orbit will be $.........R$.

The total energy of an electron in the $n^{th}$ orbit of a hydrogen atom is $E_n$. The total energy of an electron in the $n^{th}$ orbit of a $He^+$ ion is .........

Kinetic energy of an electron in one of the orbits of a hydrogen atom is $x$. Then, its total energy is . . . . . . .

$A$ diatomic molecule has moment of inertia $I$. By applying Bohr's quantization condition,its rotational energy in the $n^{\text{th}}$ level is $[n \geq 1]$ $(h = \text{Planck's constant})$

In the Bohr model of hydrogen,the force on the electron depends on the principal quantum number $n$ as: