Reflection & Transmission Of EM Waves
Reflection & Transmission of EM WavesReading – Shen and Kong – Ch. 4Outline Everyday Reflection Reflection & Transmission (Normal Incidence) Reflected & Transmitted Power Optical Materials, Perfect Conductors, Metals1
TRUE or FALSE1. Destructive interference occurs when two waves areoffset by a phase of ½πm, or half a wavelength.2. The intensity of a plane wave oscillates in time. Thismeans it is always constructively and destructivelyinterfering with itself.3. In a double-slitexperiment, asyou decrease thespace betweenthe slits, theinterferencepeaks ectionBarrier withdouble cedetectorscreen2
Waves in Materialsk (n jκ )Index of refractionAbsorption coefficient2κω 4πκ α cλ3ωc
Incident and Transmitted Waves Esame amplitudes HNormal Incidenceincident wavetransmitted wavereflected waveMedium 1Medium 2Incident WaveTransmitted Wave4
EM Wave ReflectionMetal ReflectionDielectric ReflectionImage in the Public DomainThin Film InterferenceMetal Reflection Kyle Hounsell. All rights reserved. This contentis excluded from our Creative Commons license.For more information, seeImage by Ali Smiles photos/77682540@N00/2789338547/ on flickrCell Phone ReflectionAM Radio Reflection5
Incident and Transmitted WavesEincident wave HNormal Incidencetransmitted wavereflected waveMedium 1 Medium 2Incident WaveKnownTransmitted WaveDefine reflectioncoefficient asReflected WaveDefine transmissioncoefficient as6
Key Takeaways Define the reflection coefficient as Define the transmission coefficient as27
E-Field Boundary ConditionsEA area A EB δ n̂ρssurfaceNormalEA Cn̂δEB is discontinuous at a surface charge.surfaceTangentialLKnown8is continuous at a surface.
H-Field Boundary Conditionsμo HA areaAδμo HB HA HB n̂surfaceNormalC Kδis continuous at a surface.n̂Tangentialis discontinuous ata surface current.L9
Incident EM Waves at Boundaries E HMedium 1Incident Waveincident waveMedium 2Known i x̂E i e jk1 zEo11 i jk1 z Hi ẑ Ei yˆ Eo eη1η110Normal Incidence
Reflected EM Waves at Boundaries E HNormal Incidencereflected waveMedium 1Reflected WaveMedium 2UnknownDEFINE REFLECTIONCOEFFICIENT AS r x̂E r e jk1 zEor1E r ( z) r yˆ o e jk1 zˆ EHη1η111
Transmitted EM Waves at Boundaries E HNormal Incidencetransmitted waveMedium 1Transmitted WaveMedium 2UnknownDEFINE TRANSMISSIONCOEFFICIENT AS r x̂E t e jk2 zEot1E t ẑ E t yˆ o e jk2 zHη2η212
Reflection & Transmission of EM Waves at Boundaries 2 E tE 1 E i E rEMedium 11 1 H i H rHMediumMedium22 2 H rH13
Reflection of EM Waves at Boundaries 1(z 0) E 2(z 0)E 1(z 0) H 2(z 0)H η 14μ
Reflectivity & Transmissivity of Waves Define the reflection coefficient as Define the transmission coefficient asWhat are the ranges for r and t? Is energy conserved?15
Reflection & Transmission of EM Waves at Boundaries E Hincident waveNormal Incidencetransmitted waveMedium 1Medium 2Additional Java simulation athttp://phet.colorado.edu/new/simulations/16
Reflectivity & Transmissivity of EM Waves Note that The definitions of the reflection and transmission coefficientsdo generalize to the case of lossy media. For loss-less media, r and t are real: For lossy media, r and t are complex: Incident Energy Reflected Energy Transmitted EnergyR r 2 fraction of incident power that is reflectedT 1 – R fraction of incident power that is transmitted17
Reflectivity of DielectricsConsider nearly-lossless optical materials. For typical dielectrics,μ1 μ2 μ0.r μ2μ1 ε2ε1μ2μ1 ε2ε1Result ε1 ε 2n1 n2 n1 n2ε1 ε 2μ1 μ2μ1 μ2Image by Will Montague 10/ on flickr18
Reflection of EM Waves at BoundariesREMEMBER:In terms ofthe index ofrefraction,assumingμ1 μ2 μ0In terms of thecharacteristicimpedancesAnimations Dr. Dan Russell, Kettering University. All rights reserved. Thiscontent is excluded from our Creative Commons license. For more information,see http://ocw.mit.edu/fairuse.What is different in the two reflected waves ?Which side is air and which side is glass ?19
Why does metal reflect light? Kyle Hounsell. All rights reserved. This content is excluded from our CreativeCommons license. For more information, see http://ocw.mit.edu/fairuse.20
Microscopic Lorentz Oscillator Model21
T-A-R-TTAR70T60Reflection %50403020TART100T-A-R-T - the material has four distinct regions of optical properties:Transmissive,ω ω0 - γ/2,Absorptive,ω0 - γ/2 ω ω0 γ/2Reflective,ω0 γ/2 ω ωpTransmissive,ω ωp22
Reflection of aNormally IncidentEM Wave from aPerfect Conductor i x̂Eo e jkzE i ŷ Eo e jkzHηoreflected waveIncident waveStanding wave patternof the E-fieldkz 2πkz πStanding wave patternof the H-fieldkz 3π/2 kz π/223
Microscopic Lorentz Oscillator Model for FREE ELECTRONS IN METALS0.50.40.3γ/2Drude Model for metals r i60.2ωp-5ωn, κ r , i0.1-10κ5 rR432Tnn1-20-25ωp-3024ω
Reflectivity of Silverγ/21006κR43280TnReflection(%)n, κ5n1ωp6040TR20ωωp25ω
Ice is more reflective than water10% reflectedby ocean water70-80% of sunlightreflected by snow2620% reflectedby vegetationand dark soil
Thin Film iroilwaterImage by Yoko Nekonomania 7/ on flickr27
MIT OpenCourseWarehttp://ocw.mit.edu6.007 Electromagnetic Energy: From Motors to LasersSpring 2011For information about citing these materials or our Terms of Use, visit: http://ocw.mit.edu/terms.
Reflection & Transmission of EM Waves Outline Reading – Shen and Kong – Ch. 4 Everyday Reflection Reflection & Transmission (Normal Incidence) Reflected & Transmitted Power Optical Materials, Perfect Conductors, Metals TRUE or FALSE . 1. Destructive interference occurs when two waves are
Reflection Product Name Reflection for IBM Reflection for HP Reflection for UNIX and OpenVMS Reflection for Se cure IT SSH Client Reflection for ReGIS Graphics Reflection X Reflection FTP Client Reflection SFTP Client Reflection NFS Client Reflection for the Multi-Host Enterprise, Professional Edition
electromagnetic waves, like radio waves, microwaves, light, and x-rays are examples of transverse waves. Longitudinal waves travel through a medium in a direction parallel to the direction of travel of the wave. Mechanical waves such as sound waves, seismic waves created by earthquakes, and explosions are all examples of longitudinal waves.
Q: What are mechanical waves? A: Waves that require a medium in which to travel. A medium is the _ that waves travel through o Mediums can be solid, liquid, or gas Examples of mechanical waves include sound waves, seismic waves, ocean waves, etc Q: Describe two types of mechanical waves.
College physics Semester 2 Unit 2 What is a wave? How do they act? How are do waves differ? 1/29 Pre-test Waves on a String. Notes: Introduction to Waves . Lab: Waves on a String Activity (PhET) Do: read 12.3 p457 (1,3,5) 1/30 Clicker questions: Waves on a String. Lab: Fourier-Making Waves part 1 (PhET) 2/1 Lab: Fourier-Making Waves part 2 (PhET)
3. WAVES CLA Epic Plugin User Guide CLA Epic User Guide Introduction Thank you for choosing Waves!. 4. WAVES JJP Drums Plugin User Guide WAVES JJP DRUMS User Guide Chapter 1 - Introduction Welcome. 5. WAVES CLA-3A Compressor Limiter Plugin User Manual CLA-3A Compressor Limiter Plugin WAVES CLA-3A User Manual TABLE OF. 6. WAVES CLA-2A .
electromagnetic waves we can see. We see these waves as the colors of the rainbow. Each color has a different wavelength. Red has the longest wavelength and violet has the shortest wavelength. When all the waves are seen together, they make white light. Visible light waves are the only electromagnetic waves we can see.
Properties of EM Waves Electromagnetic waves are transverse waves Electromagnetic waves travel at the speed of light Because em waves travel at a speed that is precisely the speed of light, light is an electromagnetic wave Electromagnetic waves carry energy as they travel through space, and this energy can be transferred to objects
The grade 10 ELA Reading Comprehension test included three separate test sessions. Sessions 1 and . 2 were both administered on the same day, and Session 3 was administered on the following day. Each session included reading passages, followed by multiple-choice and open-response questions. Common reading passages and test items are shown on the following pages as they appeared in test .
