CP Physics
Ms. Morrison
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Pitch: a person’s impression of a sound’s
frequency
Infrasonic: sounds below 20 Hz
Ultrasonic: sounds above 20,000 Hz
Compression: high pressure region of the
sound wave, medium pushed together
Rarefaction: low pressure region of the sound
wave, medium spreads out
Loudness: a person’s impression of sound
intensity (proportional to wave’s amplitude)
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Forced vibration: vibration of an object caused
by contact with another vibrating object
Natural frequency: frequency at which
minimum energy needed to make the material
of the object vibrate and requires the least
amount of energy to continue the vibrations
Resonance: when the forced vibration of an
object matches its natural frequency and causes
a dramatic increase in the amplitude
Beat: difference between the frequencies of
two sounds heard together
Longitudinal
 mechanical
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It must vibrate
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20 – 20,000 Hz
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Speed of sound at 0 oC = 331 m/s
Speed of sound at 20 oC = 343 m/s
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It increases – this is because the
particles move faster and faster and
transfer the wave energy more
quickly.
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Solids
Liquids
Gases
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Decibel (dB) – logarithmic scale
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Swinging on a swing
Musical instruments
Opera singer shattering a glass
Bridge vibrations
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A reflected sound wave
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Bats –echolocation
Sonar
Ultrasound
 Seeing unborn babies
 Examine heart
 Uses Doppler shift
a.
b.
c.
d.
Brass: musician’s lips
Reed: reed
String: string against a sounding board
Other (flutes): air column within the
instrument
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Constructive interference – in phase –
causes sound to become louder
Destructive interference – out of phase –
causes sound to become softer
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The speed of light is one million
times faster than the speed of sound.
343 m/s vs. 3 x 108 m/s
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Transparent: material transmits light through
it (can see through it)
Translucent: material scatters the light it
transmits (can see light but not through it,
frosted windows)
Opaque: material does not transmit light,
cannot see through it or see light through it
Quantum theory: energy given off as bundles
of light energy called photons, explains how
light interacts with matter
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Dual theory: light moves through space as a
wave and interacts with matter as a particle
Luminous: object gives off light, ex. Sun,
lights, fire flies
Illuminated: object reflects light, ex. Moon,
mirror
Photon: particle of light energy
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Radio waves
Microwaves
Infrared
Visible light
Ultraviolet
X-rays
Gamma
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Radio waves: radio and TV (longest λ, lowest
frequency, and least energy)
Microwaves: heating food
Infrared: heat waves, used in heat lamps, night
vision goggles, remotes
Visible light: smallest part of EM spectrum,
colors of light
Ultraviolet: causes skin damage – sunburns,
can kill bacteria (on fruits and vegetables)
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X-rays: used to see teeth and bones for medical
purposes, airport security
Gamma rays: used for radiation therapy, given
off in nuclear explosions (shortest λ, highest
frequency, most energy)
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Red
Orange
Yellow
Green
Blue
Violet
Its frequency
 Higher frequency = more energy
 Lower frequency = less energy
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Illuminated: moon
 Luminous: sun
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a.
b.
c.
d.
reflect: light bounces of boundary of a new
medium
Refract: light bends as it moves from one
medium into another medium (air into water)
Diffract: light passing through small opening
spreads out on other side
Interfere: passing through 2 slits interferes
and produces light bands (constructive) and
dark bands (destructive)
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Photosynthesis
Absorb light to create electric current
(solar calculators)
Absorb light energy then release as color
of light
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Light can only pass through in one
direction – parallel to material’s
polarizing axis
Use polarized filter and turn 90o to see if
light is blocked out
Red
 Green
 Blue
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Cyan
 Magenta
 Yellow
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Two colors that produce white light
when they are added together (primary
light color + secondary light color)
Red + Cyan
Green + Magenta
Blue + Yellow
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White light is seen when all colors
reflected
Black is seen when all colors absorbed
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Magenta light: red + blue
Yellow light: red + green
Cyan light: blue + green
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Light colors = additive process
Pigments = subtractive process
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Pigments absorb some colors of light
and reflect the remaining colors of
light
R
G
G
B
Color seen is BLACK
B
R
G
Y
R
Color seen is RED
B
R
G
Y
C
Color seen is GREEN
B
R
G
C
Color seen is BLUE
B
R
G
G
M
Color seen is BLACK
B
t = 6.4 s
v = 335 m/s
d=?
v=d
t
335 = d
6.4
d = (335)(6.4)
d = 2144 ÷ 2
d = 1072 m
t = 7.2 s
v = 340 m/s
d=?
v=d
t
340 = d
7.2
d = (340)(7.2)
d = 2448 m
λ=?
f = 375 Hz
v = 530 m/s
v = λf
530 = λ (375)
375
375
λ = 1.41 m
vs = 25 m/s
f = 325 Hz
vd = 0 m/s
v = 343 m/s
f’ = ?
f’ = f (v + vd)
(v – vs)
f’ = 325 (343 + 0)
(343 – 25)
f’ = 325 (1.08)
f’ = 351 Hz
vs = 0 m/s
f = 288 Hz
vd = 32 m/s
v = 343 m/s
f’ = ?
f’ = f (v + vd)
(v – vs)
f’ = 288 (343 + 32)
(343 – 0)
f’ = 288 (1.09)
f’ = 313.92 Hz
528 – 520 Hz = 8 Hz
10.5 yrs (365d/y)(24h/d)(3600 s/h)
= 3.31128 x 108 s = t
v = 3.0 x 108 m/s
d=?
v = d/t
d = vt
d = (3 x 108)(3.31128 x 108)
d = 9.93 x 1016 m
t = 180 s
v = 3 x 108 m/s
d=?
v = d/t
d = vt
d = (3 x 108)(180)
d = 5.4 x 1010 m
d = 1.081 x 1011 m
v = 3 x 108 m
t=?
v = d/t
t = d/v
t = 1.081 x1011
3 x 108
t = 360.33 s
λ=?
f = 94.1 MHz
= 94.1 x 106 Hz
v = 3 x 108 m/s
v = λf
3 x 108 = λ (94.1 x 106)
9.41 x 106
94.1 x 106
λ = 3.19 m
λ = 620 nm
= 620 x 10-9 m
v = 3 x 108 m/s
f=?
v = λf
3 x 108 = 620 x 10-9 f
620 x 10-9 620 x 10-9
f = 4.84 x 1014 Hz
λ = 4.90 x 10-7 m
v = 3 x 108 m/s
f=?
v = λf
3 x 108 = 4.9 x 10-7 f
4.9 x 10-7 4.9 x 10-7
f = 6.12 x 1014 Hz