The energy of a photon whose frequency is $10^{12} \text{ MHz}$ is:

$A$ $160 \,W$ infrared source is radiating light of wavelength $50000 \,\mathring A$ uniformly in all directions. The photon flux at a distance of $1.8 \,m$ is of the order of ............. $m^{-2} s^{-1}$.

If $E$ and $P$ are the energy and the momentum of a photon respectively,then on reducing the wavelength of the photon:

The number of photons emitted by a $10\,W$ bulb in $10\,s,$ if the wavelength of light is $1000\,\mathring{A},$ is:

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

$1 \ J$ is equal to how many electron volt?