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7/25/2019 Final Review Chapters 7-13
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RRR Review
Chapters 7-13
Physics for Future Presidents
Yury Kolomensky
December 10, 2015
7/25/2019 Final Review Chapters 7-13
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12/03/2015 YGK, Physics for Future Presidents
Ch. 7: Oscillations and Waves Oscillations: periodic motion
Waves: propagation of oscillations through elastic
medium
! Longitudinal and transverse waves
! Wave speed
Resonance and standing waves
Sound, earthquakes
Superposition of waves! Interference, diffraction, beating
Doppler effect, sonic boom
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12/03/2015 YGK, Physics for Future Presidents
Examples of Questions
What is the Doppler Effect ? Demonstrate atleast two situations in which the Doppler
Effect appears. Describe technological uses of
the Doppler Effect.
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12/01/2015 YGK, PffP: Universe
Doppler Effect
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11/10/15 YGK, PffP: Invisible Light
Doppler Radar
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12/01/2015 YGK, PffP: Universe
Expansion of the Universe
Edwin Hubble (1929)
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Ch. 8: Light Electromagnetic radiation
! Transverse wave, oscillating electric and magneticfields
Particle/wave duality
!
Geometric optics: refraction, reflection, apertures! Wave effects: interference, diffraction
Polarization
Practical applications! Optical instruments and limits of resolution, human
eye, fiber optics
"Shannon information law
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8/35Fall 2015 PffP: Quizzes
Poll
In the pinhole camera, moreblurring occurs if(A) the hole is made very large, but not if it is
very small
(B) the hole is made very small, but not if it is
very large
(C) the hole is either very small or very large
(D) never, since there is no lens in the pinhole
camera
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Example: Pinhole Camera
http://en.wikipedia.org
"Classic angular resolution (in radians) "D/L
"(D is diameter of the iris, L is distance from iris to screen)
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Diffraction
http://cse.ssl.berkeley.edu/
Angular spread "#/D
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11/35Fall 2015 PffP: Quizzes
Poll
In the pinhole camera, moreblurring occurs if(A) the hole is made very large, but not if it is
very small
(B) the hole is made very small, but not if it is
very large
(C) the hole is either very small or very large
(D) never, since there is no lens in the pinhole
camera
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Resolution Limits Resolution of the optical instruments is
limited by
! Quality of optics
! Image resolution
"E.g. size of the image and number of pixels
! Environmental effects
"Atmosphere, vibrations, electronics noise
! Ultimate limit: wave nature of light (diffraction)"Resolution (in meters) "#R/D
"#is wavelength, R is distance to object, and D is
diameter of a erture or mirror
http://egg.astro.cornell.edu
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Examples Hubble in LEO
! D "2m, #"500 nm, R "600 km"Resolution "15 cm "6
Hypothetical spy satellite
! D "2m, #"400 nm, R "100 km"Resolution "2 cm "1
"Thats almost enough,
"But have to correct for atmospheric aberrations
"Technology for this exists (adaptive optics), but requires
fixed targets on the ground
"So reading the license plates is technically possible,
though challenging, and therefore expensive
7/25/2019 Final Review Chapters 7-13
15/35Fall 2015 PffP: Quizzes
Poll
Coulda spy satellite readlicense plates ?
(A) No, resolution is too low
(B) No, air distorts images too much
(C) Yes, with conventional technology
(D) Yes, with supersecret CIA technology
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Ch. 9: Invisible Light Electromagnetic spectrum
! Radio waves and microwaves! Infrared radiation
! Ultraviolet radiation
!
X-rays and gamma rays Blackbody radiation
Practical details
!
Green house effect, ozone layer depletion! IR imaging
! Medical imaging
"MRI, IR imaging, X-ray and CAT, PET
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Examples of Questions
Some people confuse the properties of theozone layer with the greenhouse effect.
Explain the two, pointing out the differences.
Describe the current day concerns for each,
and what action is appropriate.
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Ozone Layer
NOAA
Ozone (O3): created by UV dissociation of O2molecules
Strongly absorbs UV (and also IR)
Converted back to O2by chlorine: e.g. from chlorofluorocarbons
(CFC) like Freon!CFC destroys ozone
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11/10/15 YGK, PffP: Invisible Light
Greenhouse Effect
IR radiated
by glassIR radiated
by soil
IR radiated
by glass
Greenhouse effect: glass is transparent to visible light but opaque to IR
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12/03/2015 YGK, Physics for Future Presidents
Examples of Questions Ozone layer: thin layer of O3in stratosphere
! Absorbs UV light
! Can be destroyed by freon emissions (CFC)
! CFC ban seems to have had a positive effect
Greenhouse effect! Increase in global temperatures due to increased
concentration of CO2 and other greenhouse gasses in the
atmosphere, linked to fossil fuel burn
! Common: both are man-made effects
Differences: societal and political perception,
technology and cost of implementing solutions
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12/03/2015 YGK, Physics for Future Presidents
Ch. 10: Climate Greenhouse (blanket, hot car) effect
! Emission and absorption spectra for visible and IRlight
Scientific evidence, uncertainties, misconceptions
!
CO2emissions, surface temperatures! Long-term trends vs short-timescale fluctuations
Policy issues
!
Global CO2 emissions and energy policies
! International panels and agreements
"Kyoto protocol, Doha amendment
"IPCC
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Fall 2015 PffP: Quizzes
Poll
The country that produces themost carbon dioxide each year
is(A) United States
(B) China
(C) Russia
(D) Saudi Arabia
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Fall 2015 PffP: Quizzes
Poll
The country that produces themost carbon dioxide each year
is(A) United States
(B) China
(C) Russia
(D) Saudi Arabia
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Fall 2015 PffP: Quizzes
Poll
Global warming over the past 100years has been approximately
(A) 1o
C(B) 5oC
(C) 10oC
(D) 20oC
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Fall 2015 PffP: Quizzes
Poll
Global warming over the past 100years has been approximately
(A) 1
o
C(B) 5oC
(C) 10oC
(D) 20oC
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12/03/2015 YGK, Physics for Future Presidents
Ch.11: Quantum Physics Particle/wave duality of matter
Microscopic world is probabilistic, not
deterministic
! Heisenberg uncertainty principle
! Atomic spectra
Effects and applications
! Lasers
! Photoelectric effect! Tunneling
! Superposition of states
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12/03/2015 YGK, Physics for Future Presidents
Examples of Questions What is special about laser light (compared,
for example, to natural sunlight) ? How does a
laser work ?
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11/17/15 YGK, PffP: QM
Lasers Basic properties
! Produce light of (nearly) same wavelength! Coherent (in phase) waves
! Emitted in (nearly) the same direction
"Focused energy
These properties have lead to a widespread technological use
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12/03/2015 YGK, Physics for Future Presidents
Ch.12: Relativity Physical laws that relate events observed by in
differentframes of reference! Galilean Relativity: everyday, common events
! Einstein, or Special Relativity: for things moving
close to a speed of light! General relativity: strong gravity
Speed of light
Energy and mass
Matter and anti-matter
Applications: GPS, black holes
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Fall 2015 PffP: Quizzes
Poll
Light from the Sun reaches us in(A) instantaneously
(B) 1 second
(C) 8 minutes
(D) 8 hours
(E) 8 thousand years
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Fall 2015 PffP: Quizzes
Poll
Light from the Sun reaches us in(A) instantaneously
(B) 1 second
(C) 8 minutes
(D) 8 hours
(E) 8 thousand years
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12/03/2015 YGK, Physics for Future Presidents
Ch. 13: The Universe
Planetary motion, solar system
! Comets and asteroids
! Exosolar planets, life on other planets
Stars, supernovae
! Heavy element production
Galaxies, universe
! The Big Bang theory
! Expansion of the Universe
! Dark matter, dark energy
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Fall 2015 PffP: Quizzes
Poll
How old is the visible Universe isclosest to ?(A) 10 thousand years
(B) 4 light years
(C)1 billion years
(D) 10 billion years(E) infinitely old
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Fall 2015 PffP: Quizzes
Poll
How old is the visible Universe(to 1 significant digit) ?(A) 6 thousand years
(B) 4 light years
(C)1 billion years
(D) 10 billion years
(E) infinitely old
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Good Luck !