The momentum of a photon in an $X-$ray beam of $10^{-10} \ m$ wavelength is

When an $X$-ray photon collides with a proton,its frequency:

In the Compton scattering process,the incident $X$-radiation is scattered at an angle of $60^{\circ}$. The wavelength of the scattered radiation is $0.22 \ \text{Å}$. The wavelength of the incident $X$-radiation in $\text{Å}$ units is:

Write the value and unit of Planck's constant.

If the momentum of a photon is $p$,then its frequency is:

The ratio of the power of a light source $S_1$ to that of the light source $S_2$ is $2$. $S_1$ is emitting $2 \times 10^{15}$ photons per second at $600 \ nm$. If the wavelength of the source $S_2$ is $300 \ nm$,then the number of photons per second emitted by $S_2$ is . . . . . . $\times 10^{14}$.