In photoelectric effect, if a weak intensity radiation instead of strong intensity of suitable frequency is used then

If $c$ is the velocity of light in free space, the correct statements about photon among the following are:

$A$. The energy of a photon is $E=h v$.

$B$. The velocity of a photon is $c$.

$C$. The momentum of a photon, $p=\frac{h v}{c}$.

$D$. In a photon-electron collision, both total energy and total momentum are conserved.

$E$. Photon possesses positive charge.

Choose the correct answer from the options given below:

Average force exerted on a non-reflecting surface at normal incidence is $2.4 \times 10^{-4} \mathrm{~N}$. If $360 \mathrm{~W} / \mathrm{cm}^2$ is the light energy flux during span of $1$ hour $30$ minutes. Then the area of the surface is:

By suitable example show that particle or wave nature depend on type of experiment.

Monochromatic light of wavelength $ 632.8\; nm$ is produced by a helium-neon laser. The power emitted is $9.42 \;mW$.

$(a)$ Find the energy and momentum of each photon in the light beam,

$(b)$ How many photons per second, on the average, arrive at a target irradiated by this beam? (Assume the beam to have uniform cross-section which is less than the target area), and

$(c)$ How fast does a hydrogen atom have to travel in order to have the same momentum as that of the photon?

Monochromatic light of frequency $6 \times 10^{14} \mathrm{~Hz}$ is produced by a laser. The power emitted is $2 \times 10^{-3} \mathrm{~W}$. How many photons per second on an average, are emitted by the source?

(Given $\mathrm{h}=6.63 \times 10^{-34} \mathrm{Js}$ )