Calculating amount of photons


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Phoebe Chen 4I
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Calculating amount of photons

Postby Phoebe Chen 4I » Sun Oct 07, 2018 1:43 pm

Does anyone know how to calculate the second part of the question? How many photons of infrared radiation does the lamp generate in 1.0s? Is there a mathematical equation?
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Ashley Zhu 1A
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Re: Calculating amount of photons

Postby Ashley Zhu 1A » Sun Oct 07, 2018 2:15 pm

After finding the energy of a photon using the equation, E = hf (f = frequency), you just need to divide the total energy emitted (11J) by the energy per photon to get the number of photons: 11J/(1.074 x 10^-19 J).

505194972 3k
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Re: Calculating amount of photons

Postby 505194972 3k » Sun Oct 07, 2018 3:08 pm

Ashley Zhu 1E wrote:After finding the energy of a photon using the equation, E = hf (f = frequency), you just need to divide the total energy emitted (11J) by the energy per photon to get the number of photons: 11J/(1.074 x 10^-19 J).


How did you find that value for energy per photon?

Ashley Zhu 1A
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Joined: Fri Sep 28, 2018 12:16 am

Re: Calculating amount of photons

Postby Ashley Zhu 1A » Sun Oct 07, 2018 5:27 pm

The energy per photon can be found using the equation E = hv where h is Planck's constant and v is the frequency, which you can find from the given wavelength with the [speed of light = wavelength x frequency] equation.

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Re: Calculating amount of photons

Postby Chem_Mod » Sun Oct 07, 2018 5:47 pm

You can use the following equation to find the amount of energy per photon:

Plug in the values, but you would need to convert 1850nm to m.

Planck's constant can be substituted for h

With units cancelled, E would then equal per photon. Because you know the total amount of Joules emitted (11J), you could then divide 11J/1.074*10^-19 J to find the total number of photons.


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