$n$ photons of wavelength $\lambda$ are absorbed by a black body of mass $m$. The momentum gained by the body is

Assertion: The energy $(E)$ and momentum $(p)$ of a photon are related by $p = E/c$.
Reason: The photon behaves like a particle.

Monochromatic light of frequency $6.0 \times 10^{14} \;Hz$ is produced by a laser. The power emitted is $2.0 \times 10^{-3} \;W$.
$(a)$ What is the energy of a photon in the light beam?
$(b)$ How many photons per second,on an average,are emitted by the source?

Monochromatic light of frequency $6 \times 10^{14} \,Hz$ is produced by a laser. The power emitted is $2 \times 10^{-3} \,W$. How many photons per second on an average are emitted by the source? (Given $h = 6.63 \times 10^{-34} \,Js$)

$A$ transmitter of power $10 \text{ kW}$ emits radio waves of wavelength $500 \text{ m}$. The number of photons emitted per second by the transmitter is of the order of:

The number of photons emitted by a $10\,W$ bulb in $10\,s,$ if the wavelength of light is $1000\,\mathring{A},$ is: