Light of a certain frequency and intensity incident on a photosensitive material causes the photoelectric effect. If both the frequency and intensity are doubled,the photoelectric saturation current becomes

Consider the two following statements $A$ and $B$, and identify the correct choice given in the answers :
$(A)$ In photovoltaic cells, the photoelectric current produced is not proportional to the intensity of incident light.
$(B)$ In gas-filled photoemissive cells, the velocity of photoelectrons depends on the wavelength of the incident radiation.

Why is photoelectric current proportional to intensity?

$A$ point source of light is used in an experiment of photoelectric effect. If the distance between the source and the photoelectric surface is doubled, which of the following may result?

$A$ photosensitive material is at $9\,m$ to the left of the origin and the source of light is at $7\,m$ to the right of the origin along the $x$-axis. The photosensitive material and the source of light start from rest and move,respectively,with $8\widehat{i}\,m/s$ and $4\widehat{i}\,m/s$. The ratio of intensities at $t = 0$ to $t = 3\,s$ as received by the photosensitive material is:

Define saturation current,stopping potential,and cut-off frequency in the context of the photoelectric effect.