Contents Reflections Why they occur Preventing Types Angles Superposition Definition ConstructiveDestructive Why Reflections Occur Reflections occur at any abrupt change in medium Demo wave device Fixed Free change ID: 466366
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Slide1
Reflections and Superposition
Contents:
Reflections
Why they occur
Preventing
Types
Angles
Superposition
Definition
Constructive/DestructiveSlide2
Why Reflections Occur
Reflections occur at any
abrupt change in mediumDemo wave device - Fixed, Free, changeSlide3
Why Reflections Occur
Reflections occur at any
abrupt
change in medium
Light Reflecting
Slide4
Why Reflections Occur
Reflections occur at any
abrupt
change in medium
Sound Reflecting
Slide5
Why Reflections Occur
Reflections occur at any
abrupt change in mediumMore examples: Waves off islands - Polynesian navigators
Long Distance telephone calls:
Your
phone
Their
phone
US Phone system
Cable or satellite
French phone systemSlide6
Preventing reflections
Reflections occur at any
abrupt change in medium2 ways to prevent reflection:Make there be no change in medium
Make the change less abrupt (i.e. gradual)
8
ohms
4
ohms
Your Stereo
Your Speaker
8
ohms
4
ohms
Impedance
TransformerSlide7
Preventing reflections
Reflections occur at any
abrupt change in medium2 ways to prevent reflection:Make there be no change in mediumMake the change less abrupt (i.e. gradual)
More examples: -
Wave device demo
Coatings on telescope lenses
Acoustic impedance transformer (demo)
Bells on hornsSlide8
An anechoic room
Wave energy is dissipated
Note lack of reflective surfaces
Voice of tour guideSlide9
Types of reflections:
Fixed ends invert:
(demo)
Free ends do not:
(demo)Slide10
Angle of incidence = angle of reflection:
Note unusual measure of angle
Right angle corners
(prisms and Mt. St. Helens center)
Demo -
laser/physics grooming mirror/Wash. Sq. Mall/sound in cornersSlide11
Angle of incidence = angle of reflection:Slide12
Smooth surfaces vs. rough
Every object reflects some light
Not always a mirrorSlide13
Field Trip time:
Hallway/commons
Lecture hall