If energy of $15 \ eV$ is given to an electron in the $4^{th}$ orbit,find its final energy when it comes out of the $H$-atom. (in $eV$)

If the energy of an electron in the first Bohr orbit of the $H$-atom is $-2.18 \times 10^{-18} \text{ J}$, then the energy of the electron in the second orbit will be:

The energy required to knock out the electron in the third orbit of a hydrogen atom is equal to

What is the energy of an electron in a hydrogen atom in a stationary state corresponding to $n = 2$ ?

In hydrogen and hydrogen-like atoms,the ratio of the difference of energies $E_{4n}-E_{2n}$ and $E_{2n}-E_{n}$ varies with its atomic number $Z$ and $n$ as:

When a hydrogen atom is raised from the ground state to an excited state,