## Calculating amount of photons

Phoebe Chen 4I
Posts: 55
Joined: Fri Sep 28, 2018 12:29 am

### Calculating amount of photons

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?
Attachments Ashley Zhu 1A
Posts: 69
Joined: Fri Sep 28, 2018 12:16 am

### Re: Calculating amount of photons

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
Posts: 27
Joined: Fri Sep 28, 2018 12:25 am

### Re: Calculating amount of photons

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
Posts: 69
Joined: Fri Sep 28, 2018 12:16 am

### Re: Calculating amount of photons

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.

Chem_Mod
Posts: 17947
Joined: Thu Aug 04, 2011 1:53 pm
Has upvoted: 406 times

### Re: Calculating amount of photons

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.