The momentum of a photon with a wavelength of $5000\,\mathring{A}$ is:

The radiation with frequency $1.0 \times 10^{14} \ Hz$ lies in the infrared region. The energy of one photon of this radiation in joules is:

If $h$ is Planck's constant in $SI$ system,the momentum of a photon of wavelength $0.01 \, \mathring{A}$ is:

The momentum of a photon of light of frequency $f$ is . . . . . . .

Two sources of light emit $X$-rays of wavelength $1 \ nm$ and visible light of wavelength $500 \ nm$,respectively. Both sources emit light of the same power $200 \ W$. The ratio of the number of photons emitted per second by the $X$-ray source to the number of photons emitted per second by the visible light source is:

$A$ photon of $1.7 \times 10^{-13} \ J$ is absorbed by a material under special circumstances. The correct statement is: