The energy flux of sunlight reaching the surface of the earth is 1.388 × 103 W/m2. How many photons are incident on the Earth per second/square meter? Assume an average wavelength of 550 nm
Power of sunlight per m2=P=1.388×103W/m2 Average λ=550×10−9m Let n be no. of photons per m2 incident on earth per second. P=nE; E=hc/λ⇒n=3.84×1021 photons/m2/s
