Lecture-26-04-17-08 - 1 1 2 ) , ( / 5 2 = T k hc B e hc T I...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon

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

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

Unformatted text preview: 1 1 2 ) , ( / 5 2 = T k hc B e hc T I Lecture-26 Blackbody Radiation Wiens Displacement law relates wavelength at maximal emission to temperature as: Max Planck asserts: i) Emission spectrum from heated surface is same as that from cavity at same temperature; solid surface has emissivity <1 whereas cavity has =1. Cavity absorbs and re- radiates at own temperature; ii) Cavity emits photons at where h = 6.626 10-34 J s; iii) Plancks theory gives = hf P T = 2.90 10-3 m K 2 Physical Optics - Particle-like Effects Photoelectric Effect Experiment: i) Light incident on metallic surface ejects electrons if < min . ii) At given , photoelectrons have maximum kinetic energy, eV max = K max . iii) Photoelectron current scales with light intensity at given applied electric field. iv) Making use of Plancks theory, Einstein showed that K max is frequency dependent: , where W o is work function. Granularity in interference image field of light at low intensity suggests particle-like nature of light: Decreasing Light Intensity K max = hf - W o Sodium 3...
View Full Document

This note was uploaded on 04/21/2008 for the course PHYSIC 2 taught by Professor Kim during the Spring '08 term at Lehigh University .

Page1 / 9

Lecture-26-04-17-08 - 1 1 2 ) , ( / 5 2 = T k hc B e hc T I...

This preview shows document pages 1 - 3. Sign up to view the full document.

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