The minimum number of photons per second?

girlygirl55

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

An owl has good night vision because its eyes can detect a light intensity as small as 4.5 10-13 W/m2. What is the minimum number of photons per second that an owl eye can detect if its pupil has a diameter of 7.5 mm and the light has a wavelength of 503 nm?



2. Relevant equations

I'm not really sure how to begin. Can you help me solve this step by step?

Photons per sec= Energy per sec/Energy per photon ??


3. The attempt at a solution

diazona

Sure, that'd be a good start.