The beam of light has three wavelengths $4144 \,\mathring A$, $4972 \;\mathring A$ and $6216\; \mathring A$ with a total intensity of $3.6 \times$ $10^{-5}\,Wm ^2$ equally distributed amongst the three wavelengths. The beam falls normally on the area $1\,cm ^2$ of a clean metallic surface of work function $2.3\,eV$. Assume that there is no loss of light by reflection and that each energetically capable photon ejects one electron. Calculate the number of photoelectrons liberated in $2\,s$.
$2 \times 10^9$
$1.075 \times 10^{12}$
$9 \times 10^8$
$3.75 \times 10^6$
The time taken by a photoelectron to come Out after the photon strikes is approximately
Photons of energy $6 eV$ are incident on a metal surface whose work function is $4 eV$. The minimum kinetic energy of the emitted photo-electrons will be ........... $eV$
When monochromatic radiation of intensity $I$ falls on a metal surface, the number of photoelectrons and their maximum kinetic energy are $N$ and $K$ respectively. If the intensity of radiation is $2I$, the number of emitted electrons and their maximum kinetic energy are respectively
When an inert gas is filled in the place vacuum in a photo cell, then
The work function of a metal is