The laser emits light with a wavelength of 600 nm. What is the energy of each emitted photon.

We calculate the photon energy using Planck’s formula:
E = h * ν, where h is Planck’s constant (const, h = 6.62 * 10 ^ -34 J * s), ν is the frequency of light (ν = υ / λ, where υ is the speed of propagation of light in vacuum, υ = 3 * 10 ^ 8 m / s), λ is the light wavelength (by condition λ = 600 nm = 600 * 10 ^ -9 m)).
Е = h * ν = h * υ / λ.
Let’s do the calculation:
E = 6.62 * 10 ^ -34 * 3 * 10 ^ 8 / (600 * 10 ^ -9) = 0.0331 * 10 ^ -17 J = 331 * 10 ^ -21 J = 331 zJ.
Answer: The energy of each emitted photon is 331 zJ.