Thomson's atomic model is also known as .....

The energy of an electron revolving in the $n^{th}$ Bohr's orbit of an atom is given by the expression

For which of the following species,Bohr's theory is not applicable?

Binding energy of a hydrogen atom is $13.6 \ eV$. The binding energy of a singly ionized helium atom is : ............ $eV$

The number of maximum possible different spectral lines obtained in the Balmer series,when an electron makes a transition to the ground state from the $5^{th}$ excited state in a sample of hydrogen atoms,is:

The wavelength of $H_{\alpha}$ line of Balmer series is $X \ \mathring{A}$. What is the wavelength of $H_{\beta}$ line of Balmer series?