When a hydrogen atom is in its first excited level,its radius is .... of the Bohr radius.

The angular momentum for the electron in the first Bohr orbit is $L$. If the electron is assumed to revolve in the second orbit of a hydrogen atom,then the change in angular momentum will be:

In a hydrogen atom,if $V_n$ and $V_p$ are the orbital velocities in the $n^{\text{th}}$ and $p^{\text{th}}$ orbits respectively,then the ratio $V_p : V_n$ is:

Obtain the equations for the frequency of radiation and the wave number when an electron makes a transition from a higher energy state to a lower energy state in a hydrogen atom.

What is the minimum energy that must be given to a $H$ atom in the ground state so that it can emit an $H_{\gamma}$ line in the Balmer series? If the angular momentum of the system is conserved,what would be the angular momentum of such an $H_{\gamma}$ photon?

The orbital acceleration of an electron in a hydrogen atom is given by: