Monochromatic light of frequency 6.0 * 10^{14} Hz is produced by a laser. The power emitted is 2.0 * 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?

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6.4: The Compton Effect - Physics LibreTexts
Nov 5, 2020 ... The Compton effect is the term used for an unusual result observed when X-rays are ... Describe how experiments with X-rays confirm the particle nature of radiation ... relativity and the concept of a light quantum, which we now call a photon. ... In Equation 6.4.1, E is the total energy of a particle, p is its linear ...
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Given that
Frequency of monochromatic light f = 6.0* 10^{14} Hz
Power emitted P = 2.0 * 10^{-3} W
a) What is the energy of a photon in the light beam?
Recall the photon energy equation
E = hf
Where, E - energy of photons, h - Planck constant = 6.63* 10^{-34} J and f - frequency of waves
Step 1: Substituting the known values in the photon energy equation
Photon energy E = 6.63* 10^{-34} * 6.0* 10^{14}
E = 3.98 * 10^{-19}
Thus, energy of the photon E = 3.98 * 10^{-19} J
b) How many photons per second, on an average, are emitted by the source?
The transmitted (P) power within the light equivalent to (n) times the energy per (E) photon.
P = nE
Where, n - Number of photons released per second by source
Step 1: Set up an equation for number of photons per second,
n = \frac{P}{E}
n = \frac{2.0 * 10^{-3}}{3.98 * 10^{-19}}
n = 5.0 * 10^{15}
Hence, number of photons per second n = 5.0 * 10^{15} photons per second.