Answer:
8.04 × 10¹⁶ photons per second
Explanation:
First, we calculate the energy per photon from E = hc/λ where h = Planck's constant = 6.63 × 10⁻³⁴ Js c = speed of light = 3 × 10⁸ m/s and λ = wavelength of laser = 987 nm = 987 × 10⁻⁹ m = 9.87 × 10⁻⁷ m
So, E = hc/λ = 6.63 × 10⁻³⁴ Js × 3 × 10⁸ m/s/9.87 × 10⁻⁷ m = 19.89/9.87 × 10⁻¹⁹ J = 2.02 × 10⁻¹⁹ J per photon.
Since we have a total of 0.52 J over a period of 32 s, the output power is 0.52 J/32 s = 0.0163 J/s.
Thus the total number of photons per second is thus in output power/energy per photon = 0.0163 J/s ÷ 2.02 × 10⁻¹⁹ J per photon
= 8.04 × 10¹⁶ photons per second
