Physics Lecture 14

Physics Lecture 14 - Lecture 14 Waves Particles 1800s light is a wave Maxwell light is an EM wave I Photoelectric Effect Light Metal Energy of

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
1800s light is a wave Maxwell light is an EM wave I. Photoelectric Effect a. classically – if you increase A (increase I) you see a increase in frequency of electrons b. experimentally this was not true c. If f < f t no electrons ejected, regardless of I d. If f > f t electrons are ejected, number per second grows with intensity, max kinetic energy grows with frequency e. 1905 Einstein light is composed of particles photons Energy of Photons: E ph = hf f. To eject electrons: need E ph > E binding where E binding is the work function E ph > φ electrons are ejected i. Threshhold: E ph = φ hf t = φ f t = φ/h g. K max leftover energy if f > f t K max E ph – φ = hf – φ h. Intensity = power/area Power = energy/time i. Intensity number of photons per second per meter squared 1. Frequency  Energy 2. Intensity  Number per second i. Concept test – Power = 5 for two lasers. One wavelength is 633nm and the other is 840
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/07/2008 for the course PHYS 212 taught by Professor Ladd during the Spring '08 term at Bucknell.

Page1 / 2

Physics Lecture 14 - Lecture 14 Waves Particles 1800s light is a wave Maxwell light is an EM wave I Photoelectric Effect Light Metal Energy of

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online