Which one of these is non-divisible?

$A$ radio transmitter operates at a frequency of $880 \, kHz$ and a power of $10 \, kW$. The number of photons emitted per second is:

There are two sources of light,each emitting with a power of $100 \, W$. One emits $X$-rays of wavelength $1 \, nm$ and the other visible light at $500 \, nm$. Find the ratio of the number of photons of $X$-rays to the photons of visible light of the given wavelength.

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

$A$ photon,an electron,and a uranium nucleus all have the same wavelength. The one with the most energy is:

$A$ situation of population inversion is related to