Dual nature of light is exhibited 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:

When a light source of power $P$ emitting monochromatic light of wavelength $\lambda$ is kept at a distance $r$ from a photosensitive surface of work function $\phi$ and surface area $A$,which of the following is the wrong option?

$A$ radiation of $3.8 eV$ falls on a metal surface to produce photoelectrons. These electrons are made to enter a magnetic field of $2 \times 10^{-4} T$. If the radius of the largest circular path followed by these electrons is $30 mm$,then the work function of the metal is (Mass of electron $m_{e} = 9 \times 10^{-31} kg$) (in $eV$)

Consider the following statements: $(1)$ Both wave and particle nature are required for a complete understanding of light. $(2)$ Light cannot exhibit both wave and particle nature simultaneously in a single experiment.

In the Thomson spectrograph experiment,four positive ions $P, Q, R,$ and $S$ are situated on the $Y-X$ curves as shown in the figure.