The value of threshold frequency depends on which of the following factors?

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?

$A$ photocell is illuminated by a small lamp placed at a distance of $1 \ m$. If the lamp is shifted to a distance of $2 \ m$,then the number of emitted electrons will be:

From the following graph of photo-current against collector plate potential,for two different intensities of light $I_{1}$ and $I_{2}$,one can conclude:

$A$ photocell is receiving light from a source placed at a distance of $1 \ m$. If the same source is placed at a distance of $2 \ m$,then the ejected electrons:

When a monochromatic point source of light is at a distance of $0.2\, m$ from a photoelectric cell,the cut-off voltage and the saturation current are respectively $0.6\, V$ and $18.0\, mA$. If the same source is placed $0.6\, m$ away from the photoelectric cell,then