The value of the stopping potential in the following diagram is ......... $V$.

Two metallic plates $A$ and $B$,each of area $5 \times 10^{-4} \, m^2$,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 $2 \, eV$. The electric field between the plates at the end of $10 \, seconds$ is:

The work function of aluminium is $4.2 \ eV$. If two photons, each of energy $3.5 \ eV$, strike an electron of aluminium, then the emission of electrons will be:

The figure shows a plot of photo current versus anode potential for a photo sensitive surface for three different radiations. Which one of the following is a correct statement?

Why is photoelectric current proportional to intensity?

$A$ point source causes the photoelectric effect from a small metal plate. Which of the following curves may represent the saturation photocurrent $(I)$ as a function of the distance $(r)$ between the source and the metal?