Question

Monochromatic light of frequency $6\times {10}^{14}$ Hz is produced by a laser. The power emitted is $2\times {10}^{-3}$ W
(i) What is the energy of the photon in the light beam?
(ii) How many photons per second, on an average are emitted by the source ?

Answer 1

$\to$ dual nature of radiation and matter.

givern. $V=6\times {10}^{+14}Hz$

power emitted by light $p=2\times {10}^{-3}w$

energy of one photon is given by

energy $=hv\to i$

Number of photons emitted per second $=\frac{power}{enwrgyofonephoton}$

$=\frac{2\times {10}^{-3}}{6.63\times {10}^{-34}\times 6\times {10}^{14}}$

$\Rightarrow 5.03\times {10}^{15}\to ii$