test review waves, optics, modern physics. characteristics of waves one thing all waves have in...
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Test Review
Waves, Optics, Modern Physics
Characteristics of Waves
• One thing ALL waves have in common is that they all transfer energy.
• As they travel through a medium, they move the molecules around, but eventually leave them in the same place they started.
Characteristics of Waves
• Consider the following wave: Frequency = 10 Hz
20 m
4 m
Characteristics of Waves
• What is it’s amplitude? Frequency = 10 Hz
20 m
4 m
Characteristics of Waves
• What is it’s amplitude? Frequency = 10 Hz
20 m
4 m
Characteristics of Waves
• What is it’s amplitude? Frequency = 10 Hz
20 m
4 m
10 m
Characteristics of Waves• What is it’s wavelength (λ)?
Frequency = 10 Hz
20 m
4 m
Characteristics of Waves• What is it’s wavelength (λ)?
Frequency = 10 Hz
20 m
4 m
Characteristics of Waves• What is it’s wavelength (λ)?
Frequency = 10 Hz
20 m
4 m
8 m
Characteristics of Waves
• What is it’s period? Frequency = 10 Hz
20 m
4 m
Characteristics of Waves
• What is it’s period? Frequency = 10 Hz
20 m
4 m
Period = 1/f
Characteristics of Waves
• What is it’s period? Frequency = 10 Hz
20 m
4 m
Period = 1/f
sec1.010
1
Hz
T
Characteristics of Waves
• What is it’s velocity? Frequency = 10 Hz
20 m
4 m
Characteristics of Waves
• What is it’s velocity? Frequency = 10 Hz
20 m
4 m
fv
Characteristics of Waves
• What is it’s velocity? Frequency = 10 Hz
20 m
4 m
fv
smv
mHzv
/80
)8)(10(
Characteristics of Waves
• Example: A radio wave has a frequency of 104 kHz. What is its wavelength?
Characteristics of Waves
• Example: A radio wave has a frequency of 104 kHz. What is its wavelength?
Fact: Radio waves travel at the speed of light, so we know that v=3.0E8m/s for the radio wave.
Characteristics of Waves
• Example: A radio wave has a frequency of 104 kHz. What is its wavelength?v=3.0E8m/s f= 104kHz= 104,000Hz
Characteristics of Waves
• Example: A radio wave has a frequency of 104 kHz. What is its wavelength?v=3.0E8m/s f= 104kHz= 104,000Hz
fv
Characteristics of Waves
• Example: A radio wave has a frequency of 104 kHz. What is its wavelength?v=3.0E8m/s f= 104kHz= 104,000Hz
fv
m
E
HzsmE
6.2884
000,104
80.3
)000,104(/80.3
Characteristics of Waves
• Frequency vs. Period.
• Frequency is the inverse of Period so it means that the graph looks like this:
Period
Freq
uenc
y
Characteristics of Waves
• An singer can break glass if they sing a note that has the same what as the glass?
Characteristics of Waves
• An singer can break glass if they sing a note that has the same what as the glass?
Natural Frequency
Types of Waves
• What kind of wave is each: Transverse or compressional?
Light ??
Sound ??
Types of Waves
• What kind of wave is each: Transverse or compressional?
Light Transverse
Sound Compressional
The Doppler Effect
• Which side will hear a lower pitch and which side a higher pitch?
The Doppler Effect
LOWER PITCH HIGHER PITCH
Wave Interference
• What will the resultant amplitude be as these two waves overlap?
2x x
Wave Interference
• What will the resultant amplitude be as these two waves overlap?
3x
Test Review
•Optics
The Lens/Mirror Formula
• This formula works for ALL mirrors and lenses.• It doesn’t matter if they are concave or
convex.
f
Real Pencil
Pencil’s Reflection
p
q
The Lens/Mirror Formula
• This formula works for ALL mirrors and lenses.• It doesn’t matter if they are concave or
convex.
f
Real Pencil
Pencil’s Reflection
p
q
fqp
111
The Lens/Mirror Formula
• An object is placed 50 cm in front of a mirror with a focal length of 30 cm. What is the image distance from the mirror?
The Lens/Mirror Formula
• An object is placed 50 cm in front of a mirror with a focal length of 30 cm. What is the image distance from the mirror?p= 50cm f= 30cm q=?
The Lens/Mirror Formula
• An object is placed 50 cm in front of a mirror with a focal length of 30 cm. What is the image distance from the mirror?p= 50cm f= 30cm q=?
cmcmq
cmqcm
fqp
50
1
30
11
30
11
50
1
111
qcm
q
q
0.75
013.01
013.01
The Lens/Mirror Formula
• Find the magnification of the same mirror.
The Lens/Mirror Formula
• Find the magnification of the same mirror.
We can find magnification by p
q
The Lens/Mirror Formula
• Find the magnification of the same mirror.p= 50cm q= 75cm
Magnification equals
5.150
75
cm
cm
p
q
Snell’s Law
• The Index of Refraction (n) tells us how fast light travels through a medium.
• As n gets lower, light travels faster. Light travels fastest in a vacuum.
Snell’s Law
• Example: A beam of light travels from crystal into water with an angle of incidence of 60° and an angle of refraction of 50°. Find the index of refraction of the crystal. (nwater=1.33)
Snell’s Law
• Example: A beam of light travels from crystal into water with an angle of incidence of 60° and an angle of refraction of 50°. Find the index of refraction of the crystal. (nwater=1.33)
Snell’s Law: n1sinθ1= n2sinθ2
.
Snell’s Law
• Example: A beam of light travels from crystal into water with an angle of incidence of 60° and an angle of refraction of 50°. Find the index of refraction of the crystal. (nwater=1.33)
Snell’s Law: n1sinθ1= n2sinθ2
18.187.
01.1
01.187.0
50sin33.160sin
1
1
1
n
n
n
Modern Physics
Half Life
• Over time radioactive stuff looses it’s mass because of radiation.
• A Half Life is the amount of time it takes for half of a sample to disappear.
• i.e.- If 1kg of stuff has a half life of 10min. After 10min, there is only 0.5kg left.
Half Life
• If a 10kg sample of a radioactive substance has a half life of 5 sec, how much will be left after 15 sec?
Half Life
• If a 10kg sample of a radioactive substance has a half life of 5 sec, how much will be left after 15 sec?
-How many half lives go past in 15 sec?
Half Life
• If a 10kg sample of a radioactive substance has a half life of 5 sec, how much will be left after 15 sec?
-How many half lives go past in 15 sec? 3
Half Life
• If a 10kg sample of a radioactive substance has a half life of 5 sec, how much will be left after 15 sec?
-How many half lives go past in 15 sec? 3
So… divide 10kg by 2 three times…
Half Life
• If a 10kg sample of a radioactive substance has a half life of 5 sec, how much will be left after 15 sec?
-How many half lives go past in 15 sec? 3
So… divide 10kg by 2 three times…
kgkg 25.122210
Atomic Energy
• Nuclear reactions can transfer matter into energy.
• One type of reaction is Fusion.
Atomic Energy
• Nuclear reactions can transfer matter into energy.
• One type of reaction is Fusion.
• An example of fusion would be two Hydrogen atoms colliding and turning into a Helium atom and releasing energy. In the sun.
HeHH 42
21
21
Antimatter
• Matter and antimatter can also come together to release energy in a process called annihilation.
The amount of energy released is equal to:
2mcE
Antimatter
• Comparison of regular matter and it’s antimatter opposite…
Matter vs. AntimatterMATTER ANTIMATTER
Electron Positron
Mass= 9.1E-31 kg Mass= 9.1E-31kg
Charge = Negative Charge = Positive
Antimatter
• How much energy is released when an electron and positron come together and annihilate?
Antimatter
• How much energy is released when an electron and positron come together and annihilate?
smEc
kgEm
kgEm
/80.3
311.9
311.9
2
1
Antimatter
• How much energy is released when an electron and positron come together and annihilate?
smEc
kgEm
kgEm
/80.3
311.9
311.9
2
1
JEE
EEE
EEEE
mcE
13638.1
)169)(312.18(
)80.3)(311.9311.9( 2
2
Electromagnetic Spectrum
• The electromagnetic spectrum comprises all the types of electromagnetic waves from radio waves to gamma rays.
Electromagnetic Spectrum
• All electromagnetic radiation travels at the same speed. The speed of light.
Electromagnetic Spectrum
• The spectrum is made up of the following kinds of waves:
TYPE
Radio
Microwaves
Infrared
Visible Light
Ultraviolet (UV)
X-ray
Gamma
Electromagnetic Spectrum
• The spectrum is made up of the following kinds of waves:
TYPE
Radio
Microwaves
Infrared
Visible Light
Ultraviolet (UV)
X-ray
Gamma
WAVELENGTH (λ)
Longest
Shortest
Electromagnetic Spectrum
• The spectrum is made up of the following kinds of waves:
TYPE
Radio
Microwaves
Infrared
Visible Light
Ultraviolet (UV)
X-ray
Gamma
WAVELENGTH (λ)
Longest
Shortest
FREQUENCY (f)
Lowest
Highest
Electromagnetic Spectrum
• The spectrum is made up of the following kinds of waves:
TYPE
Radio
Microwaves
Infrared
Visible Light
Ultraviolet (UV)
X-ray
Gamma
WAVELENGTH (λ)
Longest
Shortest
FREQUENCY (f)
Lowest
Highest
ENERGY
Least
Most
Test
• 20 Multiple Choice (80 pts)• 1 Constructed Response (20 pts)