At noon on a clear day, sunlight reaches the earth\'s surface at Madison, Wisconsin, with an average power of approximately 7.00 kJ·s–1·m–2. If the sunlight consists of photons with an average wavelength of 510.0 nm, how many photons strike a 8.40 cm2 area per second?

Answer 1

E = hc/wavelength
Substitute wavelength and solve for E = ? J/photon.

7 kJ/s/m^2 x 8.40 cm^2 x *(1 m/100 cm)^2 x (1 kJ/1000J) = Joules striking 8.40 cm^2 area.
Then ? J/photon x # photons = J striking 8.40 cm^21 area.
Solve for # photons.