In Bohr's model,if the atomic radius of the first orbit is ${r_0}$,then the radius of the fourth orbit is

When an electron jumps from the $n = 4$ level to the $n = 1$ level,the angular momentum of the electron changes by:

At which excited state of $Be^{3+}$ will the radius of the $e^{-}$ be the same as that of an $H$ atom in the ground state?

In the Bohr model of the hydrogen atom, the electron is pictured to rotate in a circular orbit of radius $5 \times 10^{-11} \, m$, at a speed of $2.2 \times 10^{6} \, m/s$. What is the current associated with the electron's motion (in $ \, mA$)?

Consider a hydrogen-like ionized atom with atomic number $Z$ with a single electron. In the emission spectrum of this atom,the photon emitted in the $n = 2$ to $n = 1$ transition has energy $74.8 \ eV$ higher than the photon emitted in the $n = 3$ to $n = 2$ transition. The ionization energy of the hydrogen atom is $13.6 \ eV$. The value of $Z$ is:

The ratio of the speed of an electron in the ground state of the Bohr's first orbit of a hydrogen atom to the velocity of light in air is: