The intensity of electromagnetic radiation from the sun reaching the earth's upper atmosphere is 1.37kW/m2kW/m2. Part A Assuming an average wavelength of 680 nmnm for this radiation, find the number of photons per second that strike a 1.50 m2m2 solar panel directly facing the sun on an orbiting satellite.

#_photon = 7  10²¹ photons

Explanation:

Let's look for the power that affects the panel of area of 1.5 m2

           I = P / A

           P = I A

           P = 1.37 10³  1.5

           P = 2,055 10³ W

           P = E / t

If we use t = 1 s

           E = P t

           E = 2,055 10³ J

This is the power that the panel receives, let's look for the energy of a photon

            E = h f

            c = λ f

            f = c /λ

            E = h c /λ

Let's calculate

            E₀ = 6.63 10⁻³⁴  3 10⁸/680 10⁻⁹

            E₀ = 2.925 10⁻¹⁹ J

In one second the total energy is the number of photons for the energy of each one

             E = #_photon  E₀

             #_photon = E / E₀

             #_photon = 2,055 10³ / 2,925 10⁻¹⁹

            #_photon = 7  10²¹ photons

b. a lightning bug, plug of grass, and a worm