$A$ point source of light is used in an experiment on the photoelectric effect. Which of the following curves best represents the variation of photocurrent $(i)$ with distance $(d)$ of the source from the emitter?

Assertion : Photoelectric saturation current increases with the increase in frequency of incident light.
Reason : Energy of incident photons increases with increase in frequency and as a result photoelectric current increases.

Threshold frequency for a metal is $15 \times 10^{14} \, Hz$. The light of wavelength $6000 \, \text{Å}$ falls on the metal surface. Then photoelectrons [velocity of light in air, $c = 3 \times 10^8 \, m/s$]:

The graph shows the variation of photocurrent with anode potential for four different radiations. Let $I_a, I_b, I_c$ and $I_d$ be the intensities and $f_a, f_b, f_c$ and $f_d$ be the frequencies for the curves $a, b, c$ and $d$ respectively,then

In the photoelectric effect, keeping the frequency of incident radiation and the accelerating potential fixed, if the intensity of incident light is increased,

Give an outline of the experimental study of the photoelectric effect.