$A$ hydrogen atom (ionisation potential $13.6 \ eV$) makes a transition from the third excited state to the first excited state. The energy of the photon emitted in the process is.......$eV$.

Which fact indicates that the total energy of an electron in an atom is negative?

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:

An electron jumps from the $4th$ orbit to the $2nd$ orbit of a hydrogen atom. Given the Rydberg constant $R = 10^5 \text{ cm}^{-1}$. The frequency in $\text{Hz}$ of the emitted radiation will be:

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:

$A$ hydrogen atom at the ground level absorbs a photon and is excited to $n=4$ level. The potential energy of the electron in the excited state is