Monochromatic light of wavelength $667 \,\,nm$ is produced by a helium neon laser. The power emitted is $9 \,\,mW.$ The number of photons arriving per sec. on the average at a target irradiated by this beam is
$3 \times 10^{16}$
$9 \times 10^{15}$
$3 \times 10^{19}$
$9 \times 10^{17}$
Find the number of electrons emitted per second by a $24 \,W$ source of monochromatic light of wavelength $6600 \mathring A$, assuming $3 \%$ efficiency for photoelectric effect (take $h=6.6 \times 10^{-34} \,Js$ ) $S$
What is relation between photon and intensity of radiation ?
In photoelectric effect, the electrons are ejected from metals if the incident light has a certain minimum
The number of photons per second on an average emitted by the source of monochromatic light of wavelength $600\, \mathrm{~nm}$, when it delivers the power of $3.3 \times 10^{-3}$ $watt$ will be : $\left(\mathrm{h}=6.6 \times 10^{-34}\, \mathrm{Js}\right)$
The momentum of a photon in an $X-$ ray beam of ${10^{ - 10}}$ metre wavelength is