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

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.

Angular momentum of an electron in the second shell of a $Li^{+2}$ ion is:

The electron in a hydrogen atom undergoes a transition from higher orbits to an orbit of radius $476.1 \text{ pm}$. This transition corresponds to which of the following series?

The energy of an electron in the first Bohr orbit of $H$ atom is $-13.6 \ eV$. The possible energy value$(s)$ of the excited state$(s)$ for electrons in Bohr orbits of the hydrogen atom is(are) $............ \ eV$.

The postulate of Bohr theory that electrons jump from one orbit to the other,rather than flow,is according to: