The curves $(1)$,$(2)$,$(3)$,and $(4)$ show the variation between the applied potential difference $(V)$ and the photoelectric current $(i)$ at two different intensities of light $(I_1 > I_2)$. In which figure is the correct variation shown?

The work functions of Caesium $(Cs)$, Potassium $(K)$, and Sodium $(Na)$ are $2.14\,eV$, $2.30\,eV$, and $2.75\,eV$ respectively. If incident electromagnetic radiation has an incident energy of $2.20\,eV$, which of these photosensitive surfaces may emit photoelectrons?

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.

What is the photoelectric effect?

The curve between the work function of a metal $(\phi_o)$ and its temperature $(T)$ will be:

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.