When an electron moves from $L$-shell to $M$-shell,then it will be accompanied by :

Calculate the ratio of the radius of the $2^{nd}$ and $3^{rd}$ orbit of a hydrogen atom. (Note: $r_n \propto n^2$)

$A$: Thomson's atomic model is known as the plum pudding model.
$R$: The atom is considered as a positively charged sphere in which electrons are embedded.

If the wave number of radiation emitted for the electron transition from an excited state $n_2$ to the first excited state $(n_1 = 2)$ of a hydrogen atom is $\frac{5x}{36} \ m^{-1}$, the wave number of radiation absorbed for the electron transition from the same excited state $n_2$ to the next immediate higher excited state $(n_3 = n_2 + 1)$ in $m^{-1}$ is:

What is the ratio of time periods $(T_1 / T_2)$ in the second orbit of a hydrogen atom to the third orbit of a $He^{+}$ ion?

For a hydrogen atom,the energy difference between the first and second Bohr orbits is $3B/4$. What is the energy difference between the first and third Bohr orbits?