The anode voltage of a photocell is kept fixed. The wavelength $\lambda$ of the light falling on the cathode is gradually changed. The plate current $I$ of the photocell varies as follows:

In the following arrangement $y = 1.0\ mm$,$d = 0.24\ mm$ and $D = 1.2\ m$. The work function of the material of the emitter is $2.2\ eV$. The stopping potential $V_0$ needed to stop the photocurrent will be .............. $V$.

Find the number of photons emitted per second by a $25 \text{ W}$ source of monochromatic light of wavelength $6600 \text{ Å}$. What is the photoelectric current assuming $3 \%$ efficiency for the photoelectric effect?

In the photoelectric effect:
$A.$ The photocurrent is proportional to the intensity of the incident radiation.
$B.$ The maximum kinetic energy with which photoelectrons are emitted depends on the intensity of incident light.
$C.$ The maximum kinetic energy with which photoelectrons are emitted depends on the frequency of incident light.
$D.$ The emission of photoelectrons requires a minimum threshold intensity of incident radiation.
$E.$ The maximum kinetic energy of the photoelectrons is independent of the frequency of the incident light.
Choose the correct answer from the options given below:

The anode voltage of a photocell is kept constant. The wavelength of the light incident on the cathode is changed gradually. Which of the following graphs represents the variation of the photoelectric current $(I)$ with the wavelength $(\lambda)$?

Which of the following effects support the quantum nature of $EM$ radiation? $(1)$ Photoelectric effect $(2)$ Compton effect $(3)$ Doppler effect $(4)$ Field effect