reflections and superposition contents: reflections why they occur preventing types angles...
TRANSCRIPT
Reflections and SuperpositionContents:
•Reflections•Why they occur•Preventing•Types•Angles
•Superposition•Definition•Constructive/Destructive
Why Reflections Occur
TOC
Reflections occur at any abrupt change in mediumDemo wave device - Fixed, Free, change
Why Reflections Occur
TOC
Reflections occur at any abrupt change in mediumLight Reflecting
Why Reflections Occur
TOC
Reflections occur at any abrupt change in mediumSound Reflecting
Why Reflections OccurReflections occur at any abrupt change in medium
TOC
More examples: Waves off islands - Polynesian navigators Long Distance telephone calls:
Your phone
Their phone
US Phone system
Cable or satellite
French phone system
Preventing reflectionsReflections occur at any abrupt change in medium
TOC
2 ways to prevent reflection:Make there be no change in mediumMake the change less abrupt (i.e. gradual)
8 ohms
4ohms
Your Stereo Your Speaker
8 ohms
4 ohms
Impedance Transformer
Preventing reflectionsReflections 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)
TOC
More examples: -Wave device demo Coatings on telescope lensesAcoustic impedance transformer (demo)Bells on horns
An anechoic room
TOC
Wave energy is dissipatedNote lack of reflective surfacesVoice of tour guide
Types of reflections:
TOC
Fixed ends invert: (demo) Free ends do not: (demo)
Angle of incidence = angle of reflection:
TOC
Note unusual measure of angleRight angle corners(prisms and Mt. St. Helens center)Demo - laser/physics grooming mirror/Wash. Sq. Mall/sound in corners
Angle of incidence = angle of reflection:
TOC
Smooth surfaces vs. rough
TOC
Every object reflects some lightNot always a mirror
Field Trip time:Hallway/commons
Lecture hall