Physic Labs

Problem 3

Monochromatic light in vacuum has frequency f and wavelength λ. A light photon is described using Planck’s constant h and the speed of light c=3.00×10⁸ m/s; ignore interactions with matter. (a) Relate f and λ through wave propagation. (b) Derive one photon’s energy E_γ in terms of f and then λ. (c) Find momentum magnitude p_γ and check dimensions of E_γ and p_γ. Use SI units throughout and treat components as ideal exactly as specified. State sign conventions when writing equations and retain units in final results.
Using f=c/\lambda: Eγ=hc/λ\text{Using f=c/\lambda: }E_\gamma=hc/\lambda
problems.proof.analysis

Substitute the established relation and isolate the requested quantity. Keep the physical solution consistent with the initial conditions and assumptions.