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

Angular momentum of an electron in the $n^{th}$ orbit of a hydrogen atom is given by

The work functions of two metals ($M_A$ and $M_B$) are in the $1:2$ ratio. When these metals are exposed to photons of energy $6 \ eV$, the kinetic energy of liberated electrons of $M_A:M_B$ is in the ratio of $2.642:1$. The work functions (in $eV$) of $M_A$ and $M_B$ are respectively.

The radius of which of the following orbits is the same as that of the first Bohr's orbit of the hydrogen atom?

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

What is the ratio of the radius of the second Bohr orbit to the first Bohr orbit of the $H$ atom?