The ....... series is observed in the visible region of the hydrogen spectrum.

The photoelectric effect shows:

The wavelength of photon $A$ is $400 \ nm$. The frequency of photon $B$ is $10^{16} \ s^{-1}$. The wave number of photon $C$ is $10^{4} \ cm^{-1}$. The correct order of energy of these photons is:

The radiation is emitted when a hydrogen atom goes from a high energy state to a lower energy state. The wavelength of one line in the visible region of the atomic spectrum of hydrogen is $6.5 \times 10^{-7} \, m$. The energy difference between the two states is:

Two radiations having energies $E_1$ and $E_2$ as $15 \ eV$ and $45 \ eV$ respectively,then the relationship between $\lambda_1$ and $\lambda_2$ will be:

The wavelength of sodium light is $5.862 \times 10^{-16} \, m$. The energy of the photon will be .....