The dual nature of light is exhibited by

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:

Match the following columns:

Column-$I$	Column-$II$
$A$. Hallwachs $\&$ Lenard	$P$. Transformers
$B$. Franck-Hertz	$Q$. Microwave
$C$. Klystron valve	$R$. Quantization of energy levels
$D$. Nicola Tesla	$S$. Photoelectric effect

Unification of weak and electromagnetic interactions was done by

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:

In an experiment on the photoelectric effect,plates of three different metals $p, q,$ and $r$ are used,with work functions $\phi_p = 2.0\ eV$,$\phi_q = 2.5\ eV$,and $\phi_r = 3.0\ eV$,respectively. Three radiations of equal intensity with wavelengths $550\ nm, 450\ nm,$ and $350\ nm$ are incident on these plates. Which of the following $I \rightarrow V$ graphs is correct for the experimental results? $(hc = 1240\ eV\ nm)$