The number of photons per second on an average emitted by a source of monochromatic light of wavelength $600 \, nm$,when it delivers a power of $3.3 \times 10^{-3} \, W$,is: $(h = 6.6 \times 10^{-34} \, Js)$

An atom absorbs a photon of wavelength $500\,nm$ and emits another photon of wavelength $600\,nm$. The net energy absorbed by the atom in this process is $n \times 10^{-4}\,eV$. The value of $n$ is ............ [Assume the atom to be stationary during the absorption and emission process] (Take $h = 6.6 \times 10^{-34}\,Js$ and $c = 3 \times 10^8\,m/s$)

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:

The Compton effect demonstrates that .....

Show that the wavelength of electromagnetic radiation is equal to the de Broglie wavelength of its quantum (photon).

Consider a hypothetical annihilation of a stationary electron with a stationary positron. What is the wavelength of the resulting radiation? ($h =$ Planck's constant,$c =$ speed of light,$m_0 =$ rest mass)