PHYS 2004 Lecture Notes - Lecture 25: Wave Packet, Photon
1 Dec 2017
School
Department
Course
Professor
Document Summary
The photon model of light is ideal to analyze how light and matter interact at the atomic level. For everyday experience with light though, the classical way and ray models are much more appropriate. The electromagnetic wave is discrete and fairly localized. Approximate behavior since a wave packet would take a finite amount of time to be emitted or absorbed, contrary to experimental evidence. Wave packet idea, although useful, is still too classical to adequately represent a photon. For monochromatic light of frequency f, n photons have a total energy elight = nhf. In 1924 french graduate student louis-victor de broglie (cid:449)o(cid:374)dered, (cid:862)if light (cid:449)a(cid:448)es ca(cid:374) ha(cid:448)e a particle-like nature, (cid:449)hy should(cid:374)"t (cid:373)aterial particles ha(cid:448)e so(cid:373)e ki(cid:374)d of (cid:449)a(cid:448)e-like (cid:374)ature? (cid:863) De broglie thought about an analogy with light, and postulated that if a material particle of momentum p = mv has a wave-like nature, then its wavelength must be given by where h is pla(cid:374)ck"s co(cid:374)sta(cid:374)t.
