# Number of Photons and wavelength?

1. Jan 28, 2012

I read recently that the "number of photons emitted by a charged particle is inversely proportional to wavelength" with regard to Cerenkov radiations. (The wavelength refers to the radiation which is of comparatively shorter wavelength, towards the blue-end.)

I was looking for a more detailed explanation for this. A little (or a lot of) maths would help too!

Thank you.

2. Jan 28, 2012

### Staff: Mentor

3. Jan 28, 2012

@jedishrfu - I did that already! Wikipedia states,

"Around the visible spectrum, the relative intensity per unit frequency is approximately proportional to the frequency. That is, higher frequencies (shorter wavelengths) are more intense in Cherenkov radiation."

I was looking for an explanation on how (mathematically) 'relative intensity per unit frequency' and frequency are related. I know they're proportional, but I'd like a mathematical explanation/reasoning for it.

4. Jan 30, 2012

### Bill_K

There's a (rather mathematical) derivation of the Cherenkov frequency spectrum in Jackson.