A laser emits 10 mJ pulses of 532 nm light. How many photons are in each pulse?

Question

Quizplus · Accepted Answer

The energy of a single photon is given by E = hc/λ, where h is Planck's constant, c is the speed of light, and λ is the wavelength. The number of photons in a pulse is given by N = E/E_photon, where E is the energy of the pulse and E_photon is the energy of a single photon. Plugging in the given values, we get:E_photon = hc/λ = (6.626 x 10^-34 J s)(3 x 10^8 m/s)/(532 x 10^-9 m) = 3.73 x 10^-19 JN = E/E_photon = (10 x 10^-3 J)/(3.73 x 10^-19 J) = 2.68 x 10^16 photons

A Laser Emits 10 MJ Pulses of 532 Nm Light