Transcript WAVEPHENOMENA.pptx

WAVE PHENOMENA
Reflection at an Angle
Ray of light, or “ray” of sound at an angle to reflector
mirror
Incident angle
reflected angle
i   r
Virtual Ray
i
r
Normal
Normal is drawn perpendicular to boundary
Think about this next time you play pool
Refraction
Refraction: bending of a wavefront at a boundary
between two media, due to the change in velocity
Incoming wave
air
1
air
water
water
2
Slower velocity
Helpful Analogy: Marching Band
Firm Ground
Muddy Mess
Helpful Analogy: wheel on an axel
Firm Ground
Muddy Mess
Diffraction
If a sound wave hits a door opening, the sound will bend/spread
Spreading will be the most for…

Small opening
relative
to the wavelength.
d
So… smaller the
opening , the more
diffaction and the
longer the
wavelength the
more diffraction.
Diffraction

Spreading will be the most for…
• Larger barrier with
smaller gaps relative
to the wavelength.
d
• So… larger the
barrier = smaller
gaps, = more
diffaction and again,
the longer the
• wavelength the
more diffraction.
INTERFERENCE OF WAVES
The principle of superposition may be applied to waves
whenever two (or more) waves are travelling through the
same medium at the same time. The waves pass through
each other without being disturbed.
Constructive interference: Point where two waves meet in
phase to produce a wave of larger amplitude.
Destructive interference: Point where two waves meet out
of phase in order to produce waves of smaller amplitude.
http://rt210.sl.psu.edu/phys_anim/waves/indexer_waves.html
http://paws.kettering.edu/~drussell/Demos/superposition/superposition.html