Which of the following statements is true for photoelectrons emitted from a sodium metal surface?

Threshold frequency for a metal is $15 \times 10^{14} \,Hz$. The light of wavelength $6000 \text{ Å}$ falls on the metal surface. Which one of the following statements is correct? [velocity of light, $c = 3 \times 10^{8} \,m/s$]

$A$ photoelectric cell is illuminated by a point source of light $1 \ m$ away. When the source is shifted to $2 \ m$,then:

$A$ source of variable potential difference is connected across a photoelectric cell, and the photoelectric current is plotted against the applied potential difference. The graph with the broken line represents the initial curve of current versus applied potential difference. If the frequency of the incident light is increased and its intensity is reduced, which curve now represents the situation?

The curve between current $(i)$ and potential difference $(V)$ for a photo cell will be:

$A$ 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: