final review chapters 7-13

7/25/2019 Final Review Chapters 7-13

1/35

RRR Review

Chapters 7-13

Physics for Future Presidents

Yury Kolomensky

December 10, 2015


2/35

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


3/35


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.


4/35

12/01/2015 YGK, PffP: Universe

Doppler Effect


5/35

11/10/15 YGK, PffP: Invisible Light

Doppler Radar


6/35

12/01/2015 YGK, PffP: Universe

Expansion of the Universe

Edwin Hubble (1929)


7/3512/03/2015 YGK, Physics for Future Presidents

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


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


9/3510/22/15 YGK, PffP: Light

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)



Diffraction

http://cse.ssl.berkeley.edu/

Angular spread "#/D



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


12/35



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



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



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



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



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.


18/3511/10/15 YGK, PffP: Invisible Light

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


19/35

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


20/35


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


21/35


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


22/35

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


23/35


Poll

The country that produces themost carbon dioxide each year

is(A) United States

(B) China

(C) Russia

(D) Saudi Arabia


24/35


Poll

Global warming over the past 100years has been approximately

(A) 1o

C(B) 5oC

(C) 10oC

(D) 20oC


25/35


Poll

Global warming over the past 100years has been approximately

(A) 1

o

C(B) 5oC

(C) 10oC

(D) 20oC


26/35


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


27/35


Examples of Questions What is special about laser light (compared,

for example, to natural sunlight) ? How does a

laser work ?


28/35

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


29/35


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


30/35


Poll

Light from the Sun reaches us in(A) instantaneously

(B) 1 second

(C) 8 minutes

(D) 8 hours

(E) 8 thousand years


31/35


Poll

Light from the Sun reaches us in(A) instantaneously

(B) 1 second

(C) 8 minutes

(D) 8 hours

(E) 8 thousand years


32/35


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


33/35


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


34/35


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


35/35

Good Luck !

final review chapters 7-13

Documents