The energy of a hydrogen atom in its ground state is $-13.6 \ eV$. The energy of the level corresponding to the quantum number $n = 2$ (first excited state) in the hydrogen atom is......$eV$.

The minimum energy required to excite a hydrogen atom from its ground state is.....$ eV$.

If the first excitation potential of a hypothetical hydrogen-like atom is $15 \ V$,then the third excitation potential of the atom is

The binding energy of an electron in the ground state of a hydrogen atom is $13.6 \ eV$. What is the energy in $eV$ required to remove an electron from the first excited state of a $Li^{++}$ ion?

In an inelastic collision, an electron excites a hydrogen atom from its ground state to an $M$-shell state. $A$ second electron collides instantaneously with the excited hydrogen atom in the $M$-state and ionizes it. At least how much energy must the second electron transfer to the atom in the $M$-state?

In a hydrogen atom,the electron is in the $n^{th}$ excited state. It may come down to the second excited state by emitting ten different wavelengths. What is the value of $n$?