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How many photons are produced in a laser pulse of 0.497 J at 469 nm?

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E=hν where E is the energy of a single photon, and ν is the frequency of a single photon. We recall that a photon traveling at the speed of light c and a frequency ν will have a wavelength λ given by λ=λ will have an energy given by E=hcλλ=657 nm. This will be E=(6.626×10−34)(2.998×108)(657×10−9)=3.0235×10−19J So we now know the energy of one photon of wavelength 657 nm. To find out how many photons are in a laser pulse of 0.363 Joules, we simply divide the pulse energy by the photon energy or N=Epulse Ephoton=0.3633.0235×10−19=1.2×1018So there would be 1.2×1018 photons of wavelength 657 nm in a pulse of laser light of energy 0.363 Joules.
User Anand Raja
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4 votes

Answer:


1.1702* 10^(18)photons are produced in a laser pulse of 0.497 Joules at 469 nm.

Step-by-step explanation:

Energy of the laser pulse ,E'= 0.497 J

Number of photons = n

Energy of 1 photon with 469 nm wavelength = E

E' = n × E


E=(hc)/(\lambda )

h = Planck's constant =
6.626* 10^(-34)Js

c = speed of light =
3* 10^8m/s


\lambda = wavelength =
469 nm=469* 10^(-9)m


1 nm=10^(-9) m

Now put all the given values in the above formula, we get the energy of the photons.


E=(6.626* 10^(-34)Js* 3* 10^8m/s)/(469* 10^(-9)m)=4.2384* 10^(-19) J


n=(E')/(E)


n=(0.496 J)/(4.2384* 10^(-19) J)=1.1702* 10^(18) photons


1.1702* 10^(18)photons are produced in a laser pulse of 0.497 Joules at 469 nm.

User Scott Mildenberger
by
8.0k points

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