If an electron in the excited state falls to the ground state,a photon of energy $5 \ eV$ is emitted. The wavelength of the photon is nearly: (in $nm$)

If $\lambda_1$ and $\lambda_2$ are the wavelengths of the photons emitted when electrons in the $n^{\text{th}}$ orbit of a hydrogen atom fall to the first excited state and ground state respectively,then the value of $n$ is:

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 ......... $eV$.

Consider the following electronic energy level diagram of $H-$ atom. Photons associated with shortest and longest wavelengths would be emitted from the atom by the transitions labelled:

The first excited state of a hydrogen atom is $10.2 \ eV$ above the ground state. What temperature is needed to excite a hydrogen atom to its first excited state?

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.....$eV$.