If the energy of the first orbit of $He^{+}$ is $-54.4 \, eV$,then the energy of the second orbit will be ............. $eV$.

$1$ mole of photons, each of frequency $2500 \ s^{-1}$, would have approximately a total energy of:

Electrons with a kinetic energy of $6.023 \times 10^4 \ J/mol$ are evolved from the surface of a metal when it is exposed to radiation of wavelength $600 \ nm$. The minimum amount of energy required to remove an electron from the metal atom is

The photon having $6000 \ \mathring{A}$ wavelength has energy $E$. If the energy of photon is $2E$,find the wavelength of the photon.

When a hydrogen atom (ionization energy $13.6 \ eV$) jumps from the third excited state to the first excited state,the energy of the emitted photon in this process is .............. $eV$.

The frequency of the limiting line of the Lyman series in the hydrogen spectrum is ....