An electron collides elastically with an $H$-like atom and excites it from the ground state to $n = 3$. Find the energy transferred to the $H$-like atom in $eV$.

The total energy of an electron in the first excited state of the hydrogen atom is $-3.4 \ eV$. Find out its potential energy in this state.

Energy of the electron in $n^{th}$ orbit of hydrogen atom is given by $E_n = - \frac{13.6}{n^2} \ eV$. The amount of energy needed to transfer an electron from the first orbit to the third orbit is........$eV$.

In the Bohr model of the hydrogen atom,what is the energy required to remove an electron from the ground state $(n = 1)$ (in $eV$)?

When an electron transition takes place from an excited state to the ground state in a hydrogen atom, then:

What is the energy of the electron revolving in the third orbit expressed in $ eV $ (in $eV$)?