part ii electromagnetic waves 1. so far 2 we have discussed the nature of em waves some of the...
TRANSCRIPT
![Page 1: Part II Electromagnetic Waves 1. So far 2 We have discussed The nature of EM waves Some of the properties of EM waves. Now we will discuss EM waves and](https://reader031.vdocuments.us/reader031/viewer/2022020716/56649ef25503460f94c03a88/html5/thumbnails/1.jpg)
Part II
Electromagnetic Waves
1
![Page 2: Part II Electromagnetic Waves 1. So far 2 We have discussed The nature of EM waves Some of the properties of EM waves. Now we will discuss EM waves and](https://reader031.vdocuments.us/reader031/viewer/2022020716/56649ef25503460f94c03a88/html5/thumbnails/2.jpg)
So far
2
We have discussedThe nature of EM wavesSome of the properties of EM waves.
Now we will discussEM waves and optics
MirrorsLensesApplications
![Page 3: Part II Electromagnetic Waves 1. So far 2 We have discussed The nature of EM waves Some of the properties of EM waves. Now we will discuss EM waves and](https://reader031.vdocuments.us/reader031/viewer/2022020716/56649ef25503460f94c03a88/html5/thumbnails/3.jpg)
3
![Page 4: Part II Electromagnetic Waves 1. So far 2 We have discussed The nature of EM waves Some of the properties of EM waves. Now we will discuss EM waves and](https://reader031.vdocuments.us/reader031/viewer/2022020716/56649ef25503460f94c03a88/html5/thumbnails/4.jpg)
Reflection & Refraction
4
![Page 5: Part II Electromagnetic Waves 1. So far 2 We have discussed The nature of EM waves Some of the properties of EM waves. Now we will discuss EM waves and](https://reader031.vdocuments.us/reader031/viewer/2022020716/56649ef25503460f94c03a88/html5/thumbnails/5.jpg)
Reflection
5
![Page 6: Part II Electromagnetic Waves 1. So far 2 We have discussed The nature of EM waves Some of the properties of EM waves. Now we will discuss EM waves and](https://reader031.vdocuments.us/reader031/viewer/2022020716/56649ef25503460f94c03a88/html5/thumbnails/6.jpg)
Light Reflection
6
Angles of incidence measured from the NORMAL to the mirror.
For reflection – The angle of incidence equals the angle of reflection.
surface normal
sameangleincident ray exit ray
![Page 7: Part II Electromagnetic Waves 1. So far 2 We have discussed The nature of EM waves Some of the properties of EM waves. Now we will discuss EM waves and](https://reader031.vdocuments.us/reader031/viewer/2022020716/56649ef25503460f94c03a88/html5/thumbnails/7.jpg)
Principle of Least Time
7
A
Btoo longshortest path;equal angles
![Page 8: Part II Electromagnetic Waves 1. So far 2 We have discussed The nature of EM waves Some of the properties of EM waves. Now we will discuss EM waves and](https://reader031.vdocuments.us/reader031/viewer/2022020716/56649ef25503460f94c03a88/html5/thumbnails/8.jpg)
8 PHY102
Your eye focuses the diverging rays reflected by the mirror.
The light rays appear to come from behind the mirror.
An image is virtual if the light rays from a point on the object are directed as if they diverged from a point on the image, even though the rays do not actually pass through the image point.
![Page 9: Part II Electromagnetic Waves 1. So far 2 We have discussed The nature of EM waves Some of the properties of EM waves. Now we will discuss EM waves and](https://reader031.vdocuments.us/reader031/viewer/2022020716/56649ef25503460f94c03a88/html5/thumbnails/9.jpg)
Mirror, Mirror, on the wall, how big do you have to be to see it all? The strange world of images.
9
“image” you
“real” you
![Page 10: Part II Electromagnetic Waves 1. So far 2 We have discussed The nature of EM waves Some of the properties of EM waves. Now we will discuss EM waves and](https://reader031.vdocuments.us/reader031/viewer/2022020716/56649ef25503460f94c03a88/html5/thumbnails/10.jpg)
The speed of light
10
Light travel’s at a speed c in a vacuum.In an actual material, it travels a bit slower,
at a velocity of v.The speed of light depends on the material
through which it is traveling.DEFINITION – INDEX OF REFRACTION (or
refractive index):1
mediumnt transparaain light ofvelocity
vacuumain light ofvelocity n
![Page 11: Part II Electromagnetic Waves 1. So far 2 We have discussed The nature of EM waves Some of the properties of EM waves. Now we will discuss EM waves and](https://reader031.vdocuments.us/reader031/viewer/2022020716/56649ef25503460f94c03a88/html5/thumbnails/11.jpg)
Index of Refraction
11
![Page 12: Part II Electromagnetic Waves 1. So far 2 We have discussed The nature of EM waves Some of the properties of EM waves. Now we will discuss EM waves and](https://reader031.vdocuments.us/reader031/viewer/2022020716/56649ef25503460f94c03a88/html5/thumbnails/12.jpg)
Notice
12
vacuum
f
c
f
cn
fvv
cn
1
For two materials
1
2
2
1
22
11
n
n
divide
n
n
vacuum
vacuum
![Page 13: Part II Electromagnetic Waves 1. So far 2 We have discussed The nature of EM waves Some of the properties of EM waves. Now we will discuss EM waves and](https://reader031.vdocuments.us/reader031/viewer/2022020716/56649ef25503460f94c03a88/html5/thumbnails/13.jpg)
Huygen’s Principle
13
Each point on a wavefront actsas a secondary source of sphericalwaves that progress from thesource at the speed of light (whateverit may be).
A spherical wave with very large radius,behaves as a plane wave.
![Page 14: Part II Electromagnetic Waves 1. So far 2 We have discussed The nature of EM waves Some of the properties of EM waves. Now we will discuss EM waves and](https://reader031.vdocuments.us/reader031/viewer/2022020716/56649ef25503460f94c03a88/html5/thumbnails/14.jpg)
14
![Page 15: Part II Electromagnetic Waves 1. So far 2 We have discussed The nature of EM waves Some of the properties of EM waves. Now we will discuss EM waves and](https://reader031.vdocuments.us/reader031/viewer/2022020716/56649ef25503460f94c03a88/html5/thumbnails/15.jpg)
15 PHY102
.
Not there yet!
![Page 16: Part II Electromagnetic Waves 1. So far 2 We have discussed The nature of EM waves Some of the properties of EM waves. Now we will discuss EM waves and](https://reader031.vdocuments.us/reader031/viewer/2022020716/56649ef25503460f94c03a88/html5/thumbnails/16.jpg)
16
The Wave Nature of LightThe law of refraction is explained by
Huygen’s Principle
The little wavelets move slower in medium 2 than in medium 1. Doing the tangent shows how the wave fronts bend.
![Page 17: Part II Electromagnetic Waves 1. So far 2 We have discussed The nature of EM waves Some of the properties of EM waves. Now we will discuss EM waves and](https://reader031.vdocuments.us/reader031/viewer/2022020716/56649ef25503460f94c03a88/html5/thumbnails/17.jpg)
Some Geometry
17
0
0
90
90
![Page 18: Part II Electromagnetic Waves 1. So far 2 We have discussed The nature of EM waves Some of the properties of EM waves. Now we will discuss EM waves and](https://reader031.vdocuments.us/reader031/viewer/2022020716/56649ef25503460f94c03a88/html5/thumbnails/18.jpg)
18
The Wave Nature of Light
ADC2
BAD1
sin1 v1tAD
and sin 2 v2tAD
2
1
1
2
1
2
1
2
1
2
2211
1
2
2
1
2
1
2
1
/
/
sinsin
/
/
sin
sin
n
n
nc
nc
v
v
tv
tv
nn
n
n
nc
nc
v
v
If medium 1 is air, then
n1 1 and v1 c and 1 n /n
![Page 19: Part II Electromagnetic Waves 1. So far 2 We have discussed The nature of EM waves Some of the properties of EM waves. Now we will discuss EM waves and](https://reader031.vdocuments.us/reader031/viewer/2022020716/56649ef25503460f94c03a88/html5/thumbnails/19.jpg)
Snell’s Law of Refraction
19
2211 sinsin nn Law of Reflection
21
![Page 20: Part II Electromagnetic Waves 1. So far 2 We have discussed The nature of EM waves Some of the properties of EM waves. Now we will discuss EM waves and](https://reader031.vdocuments.us/reader031/viewer/2022020716/56649ef25503460f94c03a88/html5/thumbnails/20.jpg)
Another ViewOf Reflection(Huygen’s)
20
![Page 21: Part II Electromagnetic Waves 1. So far 2 We have discussed The nature of EM waves Some of the properties of EM waves. Now we will discuss EM waves and](https://reader031.vdocuments.us/reader031/viewer/2022020716/56649ef25503460f94c03a88/html5/thumbnails/21.jpg)
Both Together
21
![Page 22: Part II Electromagnetic Waves 1. So far 2 We have discussed The nature of EM waves Some of the properties of EM waves. Now we will discuss EM waves and](https://reader031.vdocuments.us/reader031/viewer/2022020716/56649ef25503460f94c03a88/html5/thumbnails/22.jpg)
22
![Page 23: Part II Electromagnetic Waves 1. So far 2 We have discussed The nature of EM waves Some of the properties of EM waves. Now we will discuss EM waves and](https://reader031.vdocuments.us/reader031/viewer/2022020716/56649ef25503460f94c03a88/html5/thumbnails/23.jpg)
23
a
bcritical
bbcriticala
ab
n
nSin
nnSinn
nn
)90sin( 0
At the critical angle andbeyond, only reflection is
possible.
![Page 24: Part II Electromagnetic Waves 1. So far 2 We have discussed The nature of EM waves Some of the properties of EM waves. Now we will discuss EM waves and](https://reader031.vdocuments.us/reader031/viewer/2022020716/56649ef25503460f94c03a88/html5/thumbnails/24.jpg)
Total Reflection – Optical Fiber
24
![Page 25: Part II Electromagnetic Waves 1. So far 2 We have discussed The nature of EM waves Some of the properties of EM waves. Now we will discuss EM waves and](https://reader031.vdocuments.us/reader031/viewer/2022020716/56649ef25503460f94c03a88/html5/thumbnails/25.jpg)
25
A cross section of a submarine communications cable.1 - Polyethylene2 - Mylar tape3 - Stranded steel wires4 - Aluminium water barrier5 - Polycarbonate6 - Copper or aluminum tube7 - Petroleum jelly8 - Optical fibers
Lengths of 100 KM are possible before amplification is necessary.
Thousands of conversations can be carried on a single fiber.
![Page 26: Part II Electromagnetic Waves 1. So far 2 We have discussed The nature of EM waves Some of the properties of EM waves. Now we will discuss EM waves and](https://reader031.vdocuments.us/reader031/viewer/2022020716/56649ef25503460f94c03a88/html5/thumbnails/26.jpg)
26
Waves on a string.
![Page 27: Part II Electromagnetic Waves 1. So far 2 We have discussed The nature of EM waves Some of the properties of EM waves. Now we will discuss EM waves and](https://reader031.vdocuments.us/reader031/viewer/2022020716/56649ef25503460f94c03a88/html5/thumbnails/27.jpg)
dichroism
27
80%
1% of opposite polarization
![Page 28: Part II Electromagnetic Waves 1. So far 2 We have discussed The nature of EM waves Some of the properties of EM waves. Now we will discuss EM waves and](https://reader031.vdocuments.us/reader031/viewer/2022020716/56649ef25503460f94c03a88/html5/thumbnails/28.jpg)
28
![Page 29: Part II Electromagnetic Waves 1. So far 2 We have discussed The nature of EM waves Some of the properties of EM waves. Now we will discuss EM waves and](https://reader031.vdocuments.us/reader031/viewer/2022020716/56649ef25503460f94c03a88/html5/thumbnails/29.jpg)
29
![Page 30: Part II Electromagnetic Waves 1. So far 2 We have discussed The nature of EM waves Some of the properties of EM waves. Now we will discuss EM waves and](https://reader031.vdocuments.us/reader031/viewer/2022020716/56649ef25503460f94c03a88/html5/thumbnails/30.jpg)
30
![Page 31: Part II Electromagnetic Waves 1. So far 2 We have discussed The nature of EM waves Some of the properties of EM waves. Now we will discuss EM waves and](https://reader031.vdocuments.us/reader031/viewer/2022020716/56649ef25503460f94c03a88/html5/thumbnails/31.jpg)
31
![Page 32: Part II Electromagnetic Waves 1. So far 2 We have discussed The nature of EM waves Some of the properties of EM waves. Now we will discuss EM waves and](https://reader031.vdocuments.us/reader031/viewer/2022020716/56649ef25503460f94c03a88/html5/thumbnails/32.jpg)
Mirage
32
![Page 33: Part II Electromagnetic Waves 1. So far 2 We have discussed The nature of EM waves Some of the properties of EM waves. Now we will discuss EM waves and](https://reader031.vdocuments.us/reader031/viewer/2022020716/56649ef25503460f94c03a88/html5/thumbnails/33.jpg)
33