Lumious intensity and flux of photons

[Vectorcrust]

Is there any quantitative relationship between luminous intensity of monochromatic light and flux of photons(number of photons/(area*second)) ?

 

[phyzguy]

Yes, there is. If I have a certain intensity of light I in Joules/(m^2-sec), and each photon carries an energy equal to h*f, then the number of photons per m^2 per sec is just:

N = I/(h*f) photons/(m^2-sec)