Energy of $H$-atom in the ground state is $-13.6 \; eV$. The energy needed to ionize a hydrogen atom which is in its second excited state is ....... $eV$.

When an electron in a hydrogen atom jumps from the third orbit to the second orbit,it emits a photon of wavelength $\lambda$. When it jumps from the fourth orbit to the third orbit,the wavelength emitted by the photon will be

The number of spectral lines emitted by atomic hydrogen that is in the $4^{\text{th}}$ energy level is

The energy of the highest energy photon of the Balmer series of the hydrogen spectrum is close to $... eV$.

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

In a hydrogen-like atom,when an electron jumps from the $M$-shell to the $L$-shell,the wavelength of the emitted radiation is $\lambda$. If an electron jumps from the $N$-shell to the $L$-shell,the wavelength of the emitted radiation will be: