Download - Ch 33 Electromagnetic Waves
![Page 1: Ch 33 Electromagnetic Waves](https://reader031.vdocuments.net/reader031/viewer/2022021923/586b8bf31a28abb26b8ba206/html5/thumbnails/1.jpg)
Chapter 33 Electromagnetic Waves
Key contents
Maxwell’s equations and EM wavesPoynting vectorRadiation pressureReflection, refraction, polarization
![Page 2: Ch 33 Electromagnetic Waves](https://reader031.vdocuments.net/reader031/viewer/2022021923/586b8bf31a28abb26b8ba206/html5/thumbnails/2.jpg)
EM waves in vacuum
In vacuum,
Ch 16:
![Page 3: Ch 33 Electromagnetic Waves](https://reader031.vdocuments.net/reader031/viewer/2022021923/586b8bf31a28abb26b8ba206/html5/thumbnails/3.jpg)
33.3: The Traveling Wave, Quantitatively:
One can show that in vacuum, the two fields are in phase, perpendicular to each other, and Em=cBm
![Page 4: Ch 33 Electromagnetic Waves](https://reader031.vdocuments.net/reader031/viewer/2022021923/586b8bf31a28abb26b8ba206/html5/thumbnails/4.jpg)
We can write the electric and magnetic fields as sinusoidal functions of position x (along the path of the wave) and time t :
Here Em and Bm are the amplitudes of the fields and, and k are the angular frequency and angular wave number of the wave, respectively.
The speed of the wave (in vacuum) is given by c.
Its value is about 3.0 x108 m/s. (defined to be 299 792 458 m/s)
33.3: The Traveling Wave, Qualitatively:
![Page 5: Ch 33 Electromagnetic Waves](https://reader031.vdocuments.net/reader031/viewer/2022021923/586b8bf31a28abb26b8ba206/html5/thumbnails/5.jpg)
33.2: Maxwell’s Rainbow:
![Page 6: Ch 33 Electromagnetic Waves](https://reader031.vdocuments.net/reader031/viewer/2022021923/586b8bf31a28abb26b8ba206/html5/thumbnails/6.jpg)
33.2: Maxwell’s Rainbow: Visible Spectrum:
![Page 7: Ch 33 Electromagnetic Waves](https://reader031.vdocuments.net/reader031/viewer/2022021923/586b8bf31a28abb26b8ba206/html5/thumbnails/7.jpg)
33.3: The Traveling Wave, Qualitatively:
# EM waves of different wavelengths are generated in different ways.
![Page 8: Ch 33 Electromagnetic Waves](https://reader031.vdocuments.net/reader031/viewer/2022021923/586b8bf31a28abb26b8ba206/html5/thumbnails/8.jpg)
33.5: Energy Transport and the Poynting Vector:
Energy flux:
![Page 9: Ch 33 Electromagnetic Waves](https://reader031.vdocuments.net/reader031/viewer/2022021923/586b8bf31a28abb26b8ba206/html5/thumbnails/9.jpg)
Example, Light Wave rms values of electric and magnetic fields:
![Page 10: Ch 33 Electromagnetic Waves](https://reader031.vdocuments.net/reader031/viewer/2022021923/586b8bf31a28abb26b8ba206/html5/thumbnails/10.jpg)
33.6: Radiation Pressure:
(total absorption)
(total reflection)
![Page 11: Ch 33 Electromagnetic Waves](https://reader031.vdocuments.net/reader031/viewer/2022021923/586b8bf31a28abb26b8ba206/html5/thumbnails/11.jpg)
33.7: Polarization:
![Page 12: Ch 33 Electromagnetic Waves](https://reader031.vdocuments.net/reader031/viewer/2022021923/586b8bf31a28abb26b8ba206/html5/thumbnails/12.jpg)
33.7: Polarization:
If the intensity of original unpolarized light is Io, then the intensity of the emerging light through the polarizer, I, is half of that.
![Page 13: Ch 33 Electromagnetic Waves](https://reader031.vdocuments.net/reader031/viewer/2022021923/586b8bf31a28abb26b8ba206/html5/thumbnails/13.jpg)
33.7: Polarization: Intensity of Polarized Light
![Page 14: Ch 33 Electromagnetic Waves](https://reader031.vdocuments.net/reader031/viewer/2022021923/586b8bf31a28abb26b8ba206/html5/thumbnails/14.jpg)
Example, Polarization and Intensity:
![Page 15: Ch 33 Electromagnetic Waves](https://reader031.vdocuments.net/reader031/viewer/2022021923/586b8bf31a28abb26b8ba206/html5/thumbnails/15.jpg)
33.8: Reflection and Refraction:
The index of refraction, n, of a medium is equal to c/v, where v is the speed of light in that medium and c is its speed in vacuum.The refraction law is also called Snell’s law.
![Page 16: Ch 33 Electromagnetic Waves](https://reader031.vdocuments.net/reader031/viewer/2022021923/586b8bf31a28abb26b8ba206/html5/thumbnails/16.jpg)
33.8: Reflection and Refraction:
![Page 17: Ch 33 Electromagnetic Waves](https://reader031.vdocuments.net/reader031/viewer/2022021923/586b8bf31a28abb26b8ba206/html5/thumbnails/17.jpg)
33.8: Reflection and Refraction:
![Page 18: Ch 33 Electromagnetic Waves](https://reader031.vdocuments.net/reader031/viewer/2022021923/586b8bf31a28abb26b8ba206/html5/thumbnails/18.jpg)
33.8: Chromatic Dispersion:
The index of refraction n encountered by light in any medium except vacuum depends on the wavelength of the light.
The dependence of n on wavelengthimplies that when a light beam consists of rays of different wavelengths, the rays will be refracted at different angles by a surface; that is, the light will be spread out by the refraction.
This spreading of light is called chromatic dispersion.
![Page 19: Ch 33 Electromagnetic Waves](https://reader031.vdocuments.net/reader031/viewer/2022021923/586b8bf31a28abb26b8ba206/html5/thumbnails/19.jpg)
33.8: Chromatic Dispersion:
![Page 20: Ch 33 Electromagnetic Waves](https://reader031.vdocuments.net/reader031/viewer/2022021923/586b8bf31a28abb26b8ba206/html5/thumbnails/20.jpg)
33.8: Chromatic Dispersion and Rainbow:
![Page 21: Ch 33 Electromagnetic Waves](https://reader031.vdocuments.net/reader031/viewer/2022021923/586b8bf31a28abb26b8ba206/html5/thumbnails/21.jpg)
Example, Reflection and Refraction of a Monochromatic Beam:
![Page 22: Ch 33 Electromagnetic Waves](https://reader031.vdocuments.net/reader031/viewer/2022021923/586b8bf31a28abb26b8ba206/html5/thumbnails/22.jpg)
Example, Reflection and Refraction of a Monochromatic Beam:
![Page 23: Ch 33 Electromagnetic Waves](https://reader031.vdocuments.net/reader031/viewer/2022021923/586b8bf31a28abb26b8ba206/html5/thumbnails/23.jpg)
33.9: Total Internal Reflection:
For angles of incidence larger than c, such as for rays f and g, there is no refracted ray and all the light is reflected; this effect is called total internal reflection. For the critical angle,
Which means that
![Page 24: Ch 33 Electromagnetic Waves](https://reader031.vdocuments.net/reader031/viewer/2022021923/586b8bf31a28abb26b8ba206/html5/thumbnails/24.jpg)
33.10: Polarization by Reflection:
Brewster angle:The reflected light of an unpolarized incident light is partially or fully polarized. When it is fully polarized (always in the direction perpendicular to the plane of incidence), the incidence angle is called the Brewster angle. In such a case, the reflected and refracted lights are perpendicular to each other.
![Page 25: Ch 33 Electromagnetic Waves](https://reader031.vdocuments.net/reader031/viewer/2022021923/586b8bf31a28abb26b8ba206/html5/thumbnails/25.jpg)
Homework:
Problems 13, 31, 40, 51, 65