# Calculating the number of photons in a wave

1. Jan 16, 2012

### Daintyg

1. The problem statement, all variables and given/known data

I am trying to answer a relatively simple question. I have been asked to compare the number of Photons in 100W light bulb and a 100W FM Radio per second. Having crunched the numbers it appears that an FM Radio wave gives out more Photons per second than a light bulb. Is this correct?

2. Relevant equations

I have used E=hc/λ

3. The attempt at a solution

I come out at 2.87x10E20 for a light (Using yellow) and 5.03x10E36 for a radio (the power depends on the wavelength)

2. Jan 16, 2012

### technician

You are correct and presumably in your calculation you found that the energy of A radio photon is much less than the energy of a visible light photon.
A radio frequency is very much less than the frequency of visible light

3. Jan 17, 2012

### Daintyg

Thank you, I was being a dumb arse.

4. Jan 17, 2012

### technician

No comment:rofl:
except to say.... don't look at yourself like that.