The energy of an electron in an orbit of an $H$-atom is:

In the following transitions of a hydrogen atom,which one corresponds to the highest frequency of emitted radiation?

If the binding energy of the electron in a hydrogen atom is $13.6 \ eV$,the energy required to remove the electron from the first excited state of $Li^{++}$ is.....$eV$.

Which of the following transitions in hydrogen atoms emit photons of highest frequency?

An electron with kinetic energy $E$ collides with a hydrogen atom in the ground state. The collision will be elastic

The energy of a hydrogen atom in the $n^{th}$ orbit is $E_n$. What will be the energy in the $n^{th}$ orbit of a singly ionized helium atom?