Two metallic plates $A$ and $B$, each of area $5 ×10^{-4}m^2$ are placed parallel to each other at a separation of $1\ cm$. Plate $B$ carries a positive charge of $33.7 \,pc$. $A$ monochromatic beam of light, with photons of energy $5\, eV$ each, starts falling on plate $A$ at $t = 0$, so that $10^{16}$ photons fall on it per square meter per second. Assume that one photoelectron is emitted for every $10^{6}$ incident photons. Also assume that all the emitted photoelectrons are collected by plate $B$ and the work function of plate $A$ remains constant at the value $2\, eV$. Electric field between the plates at the end of $10$ seconds is
$2 × 10^3 N/C$
$10^3 N/C$
$5 ×10^3 N/C$
Zero
There are ${n_1}$ photons of frequency ${\gamma _1}$ in a beam of light. In an equally energetic beam, there are ${n_2}$ photons of frequency ${\gamma _2}$. Then the correct relation is
A parallel beam of light of wavelength $900\,nm$ and intensity $100\,Wm ^{-2}$ is incident on a surface perpendicular to the beam. Tire number of photons crossing $1\,cm ^{2}$ area perpendicular to the beam in one second is :
An AIR station is broadcasting the waves of wavelength $300$ metres. If the radiating power of the transmitter is $10 kW$, then the number of photons radiated per second is
The ratio of the energy of a photon with $\lambda = 150\,nm$ to that with $\lambda = 300\,nm$ is