IQs -Winter 2000

Einstein, Relativity, and Quanta
PHYSICS 1040
MODERN PHYSICS AND COSMOLOGY: REVOLUTIONS IN PHYSICS
Winter Semester, 2000


 


























































Your Name___________________________________________
 
 













INTERACTIVE QUESTION PAPER
To be done for (before!) the class of

Monday, 10 January


 


















































Prof.'s Question: (1) Why study Science? Human Curiosity, “Religion”, Technology.
(2) Differences between science and technology - need of each for the other.
(3) Differences between science and “religion” - need of each for the other.
(4) Differences between “modern physics” and “classical physics”: the near and far; the fast and slow; the big and small
Your Answer:
 
 
 
 
 
 
 
 
 
 

Group Answer:
 
 
 
 
 
 
 
 
 
 

____________________________________________________
Your Question:
 
 
 

Your Answer:
 
 
 
 
 
 

Group Answer:
 
 















Wednesday, 12 January


 






















































Prof.'s Question: (1) What are the differences, what are the similarities, between the approaches of Aristotle, Galileo, and Plato to the problem of falling bodies?
(2) Can you think of an alternative (non-Galilean) definition of “acceleration? Why not use it/
(3) Try Exercise #9, page 257 of March’s text.
 
 














Friday, 14 January


 






















































Prof.'s Question: (1) Jane stands still on the flat bed of a truck traveling in a straight horizontal line at a steady speed of 30 meters/second. Joe is standing stationary on the side of the road, ahead of the truck. She throws a ball horizontally in the forward direction (i.e., in the direction of the truck’s motion); it takes her 0.1 second to throw the ball and it leaves her hand with a final speed (with respect to her) of 20 m/s. (a) What was the ball’s acceleration, as measured by Jane?  (b) What final speed does the ball have as measured by Joe?  (c) What would the ball’s horizontal acceleration be according to Joe?  (d) What would Jane and Joe say about the ball’s vertical acceleration?
(2) A bomb, at rest in space, explodes, breaking up into two pieces, one of which has twice the mass of the other.  (a) What can you say about the directions of motion of the two pieces?  (b)  What can you say about the speeds of the two pieces?
(3) Try Exercise #11, page 259 of March’s text.
 
 














Wednesday, 19 January


 






















































Prof.'s Question: (1) It is said that “weight is proportional to mass”. (What does “proportional” mean?)  What is the experimental foundation for this statement here on earth?  Would the statement still be true on the planet Jupiter?  How does the physical reality of the statement differ on the two planets?
(2)Would your weight change if the earth were to stop rotating about its axis?
(3) If the earth rotates on its axis and travels around the sun, why don’t we fall off?
 
 













Friday, 21 January


 


















































Prof.'s Question: (1) Compare the force and energy required to accelerate a car from 0 to 30 mi/hr to that required to keep it moving at a steady 30 mi/hr (both motions in a straight line).  (2) Compare the force and energy required to drive the car at a steady 30 mi/hr in a straight line to that required to drive it around a curve at the same speed.  (3)  Suppose it take the same time to accelerate a car from 60 mph to 70 mph as it does from 0 mph to 10 mph.  Explain why more work would be required for the former than for the latter.  (4)  Consider an isolated can of compressed gas.  Why does the gas rush out when the can is suddenly opened and why does the can (and the gas) feel cooler immediately afterwards?  (5)  Compare the work required for an “interplanetqary explorer” to “escape” from a planet with that required to be “captured” by that planet.  What does the work and what is the source of the required energy?
 
 













Monday, 24 January


 


















































Prof.'s Question: (1) Draw the electric field lines                                                   -
characterizing the collection of electric charges (two
positive ones, one negative) shown to the right.
(2) What is "action at a distance" and why were
Newton's contemporaries suspicious of it?                                 +                                                          +
(3) How does the concept of "field" deal with the
problem of "action at a distance"?
(4) What are the similarities and the differences between the gravitational force, the electrical force, and the magnetic force? (5) Try Question D on page 263 of March. (6) the siren on a police car has a natural pitch of 500 Hz. If the car is speeding towards you, what would you hear? Why?
 
 













Wednesday, 26 January


 


















































Prof.'s Question: (1)  Question E, Exercises 6 and 7, on page 263 of March.
(2)  the two cooking devices in your home both produce electromagnetic waves.  Which have a shorter wavelength, the dominant wave emitted by your stove, or those produced by your microwave oven?   Why?  Which has the greater frequency?
 
 












To be done for (before!) the class of
Friday, 28 January


 














































Prof.'s Question: Jane lives 1500 meters East of Joe; John lives 1500 meters due North of Joe.  A steady wind blows from North to South at a speed of 50 m/s (180 km/hr).  Both Jane and John have light aircraft, capable of flying at a steady speed of 100 m/s (360 km/hr) through still air.  They each wish to pay a flying visit to Joe, starting from their respective homes, and then return to these homes.  (Ignore all take off and landing times!)  (1) How long does it take John to reach Joe?  (2) How long does it take John to fly home?  (3)What is John’s total travel time?  (4) How long does it take Jane to reach Joe?  (5) What is her total flying time?  (6) If Jane and John could compare travel times, could they determine the wind speed without inquiring of the Weather Bureau?
 
 












To be done for (before!) the class of
Monday, 31 January


 














































Prof.'s Question: (1) The postulate of relativity allows two different observers to disagree about the simultaneity of two separated events (e.g., light hitting the mirrors in Fig.9.2) but does not allow such a disagreement when the two events are at the same place (e.g., the return of the two light flashes to the source in the same figure).  Why the difference??  (2)  Since simultaneity and time sequence are “relative”, is it possible for a third observer to see the rear door of the garage open after the front door opens (p.112 of March) - e.g., reversal of causality?
 
 










Wednesday, 2 February


 










































Prof.'s Question: (a) A passenger on a fast train, moving in a straight line with speed v, is playing chess on a square chessboard, whose sides are of length L, one of which is parallel to the side of the train.  The passenger discusses the game, via his moble phone, with his friend waiting ahead at the station.  The friend, a physicist believer in Einstein, pictures the chessboard in her head.  What picture does she see?
(b) Verify (or contradict) the statement, at the bottom of p.122 of the March text, that the rear of the car appears to Joe to be four times as long as the front half. (Actual appearances can be very distorted when account is taken of the finite travel time of the signals creating the appearances!)
(c) Why the difference between (a) and (c) above?
 
 











Friday, 4 February


 










































Prof.'s Question:(a) According to Joe's magnetic compass, he is 100 miles due North of Jane.  But Jane goes by the stars, according to which Joe's compass points 10 degrees East of North. How far North of Jane does she reckon Joe to be? Is there a "distance" upon which both Jane and Joe will agree?
(b)Jane starts her breakfast in the dining car of her space-train at 7:30 am, finishes at 8:00am and then walks to her cabin, 0.5 km away, ariving at 8:15 am.  The train is rushing by Joe's space station at a relative speed of 0.95c. How long does Joe think Jane spent at breakfast?  How long does Joe think it took Jane to walk back to her cabin?  How far does Joe think Jane had to walk from breakfast to her cabin?  Is there any "distance" upon which both Jane and Joe can agree?
 
 










Monday, 7 February


 










































Prof.'s Question: Sue, standing on a flat car in a very fast train, is kicking a football in a direction perpendicular to the direction of the train's motion.  Joe, standing on the ground at trackside, is watching her. (a) How does the acceleration of the football, as seen by Joe, compare with Sue's perception of the same quantity?  (b) How would Sue's measurement of the mass of the football compare with that perceived by Joe?  (c) How would their two measurements of the net force, exerted by Sue's foot on the ball, compare? Why?
 
 









To be done for (before!) the class of
Wednesday, 9 February


 






































Prof.'s Question: (a) A uranium nucleus fissions naturally into two palladium nuclei, each of which recoils from the other with a very large velocity.  If the two fission products could be weighed, how would their joint weight compare with that of the original uranium nucleus?  (b) What does the formula "E equals m c squared" (E=mc2) have to do with the Manhattan project?
 
 










To be done for (before!) the class of
Friday, 11 February


 






































Prof.'s Question: (a)  An observer, at rest on the earth’s equator, compares his clock with that of an observer in a satellite.  The satellite, is moving from West to East above the surface of the earth, following the  path of the equator; it completes each of its rotations about the earth in one hour.  How do the two clocks compare?  Explain your answer fully. (b) How does the observation of the "2.8 K background radiation" contribute to the belief in the "big bang"?
 
 









To be done for (before!) the class of
Wednesday, 16 February


 


























Prof.'s Question:  To be done for (before!) the class of(a) Give some reasons for, and some against, a belief in the physical reality of molecules.  What is the difference between a molecule and an atom?  (b) How can a knowledge of Avogodroe's Number lead to knowlege of the mass of single atoms?
 
 







To be done for (before!) the class of
Friday, 18 February


 


























Prof.'s Question: (a) What is the basis for J.J. Thomson's claim that electrons are universal constituents of atoms?  (b) What was Einstein's early contribution to solidifying belief in the existence of atoms?
 
 







To be done for (before!) the class of
Monday, 21 February


 


























Prof.'s Question: (a) Contrast "pragmatism" and "realism" and name some prominent physicist supporters of each  (b) What is meant by a "covarient physical law" and why is it important? (c) How does "quantum wholeness" differ  from Newton's world view? (d) What did Einstein mean by the "incompleteness" of quantum theory?
 
 







To be done for (before!) the class of
Wednesday, 23 February


 


























Prof.'s Question: (a) List the arguments for and against the planetary model of the atom.
(b) What were the alternatives?  How good were they?
 
 






To be done for (before!) the class of
Friday, 25 February


 






















Prof.'s Question: (a) How and why did Planck violate the precepts of Newtonian physics?
(b) What is the relation between the "photo electic effect" and the "Compton effect"? Where did they fit into the Newtonian scheme of things? (c) From the point of view of a Newtonian physicist, what was right about Bohr's model of the hydrogen atom? What was wrong?
 
 





To be done for (before!) the class of
Monday, 28 February


 






















Prof.'s Question: (a) In discussing Bohr's energy level scheme for the hydrogen atom and his planetary model for the same atom, which could be preferred by a "pragmatist", which by a "realist?    (b) What peculiarities are shared by light and electrons?  What are the differences? (c) What is the difference between an "ordinary object" and a "contextual object"?
 
 





To be done for (before!) the class of
Wednesday, 1 March


 






















Prof.'s Question: (a) List the arbitrary or paradoxical aspects of Bohr's model of the atom that are eliminated in the Schrodinger picture. Do any remain?    (b) If a photon and an electron have the same kinetic energy, which has the shorter wavelength? (c) What evidence do you have for believing that the electron is a particle?  What evidence do you have for believing it's a wave?
 
 





To be done for (before!) the class of
Friday, 3 March


 














Prof.'s Question:  (a) How do you reconcile the apparent discrepancy between the electron as "particle" and the electron as "wave"?   (b) What is the relation between the "uncertainty principle" and "wave-particle duality"?
 
 




To be done for (before!) the class of
Monday, 6 March


 














Prof.'s Question:  (a) Energy conservation is valid for both coherent  and incoherent superposition of waves but some how it is different in the two cases.  Explain how and why.   (b) What is the "spectral area code"?
 
 




To be done for (before!) the class of
Wednesday, 8 March


 














Prof.'s Question:  (a) Why can't you "tunnel" from Detroit to Windsor without paying the toll?  (b) Make a list (and discuss = clarify each item on it) of the ways in which "dynamic attributes" differ from "static attribute".  (c)  What has Heisenberg's "Uncertainty Principle" to do with the "spectral area code"?
 
 




To be done for (before!) the class of
Friday, 10 March


 










Prof.'s Question:  (a) You wish to measure the momentum of an electron.  Compare and contrast the methods for doing this utilyzed by a quantum theorist with the procedure employed by an experimentalist. (c) Compare the methods (and accuracy thereof) to be used for predicting the future path of an electron with those used for the future path of a baseball.
 
 



To be done for (before!) the class of
Monday, 20 March


 










Prof.'s Question:  (a) What is the difference between the "quantum interpretation question" and the "quantum measurement problem"? (b) What is the difference between "quantum ignorance" and "classical ignorance"? (c) What is a "hidden variable " theory and what's wrong with it?  What's right about it?
 
 



To be done for (before!) the class of
Wednesday, 22 March


 










Prof.'s Question:   (a) What is the connection between "Schrodinger's cat" and the "collapse of the wave function"? (b) How do we know that an electron "knows" whether or not more than one apperature is open to it in a barrier thru which it goes? (c) What is the meaning of the statement "reality is non-local" and how is it illustrated by the electrons of Part (b)?
 
 



To be done for (before!) the class of
Wednesday, 29 March


 










Prof.'s Question:  (a) If a theorist determines that a quon beam has a dynamic attribute which is single-valued, what will the experimentalist find when she measures the corresponding attribute? (b) Suppose that when you set your polarization meter in the vertical direction you get 100% hits from a given quon beam.  If you now apply a horizontal polarization meter to a similarly prepared beam, what do you expect to observe? (c) You are dealt a single card, face down, from a standard deck.  When does the probability of you having an ace-of clubs change to a certainty?  How does this compare with the "collapse of the wave function"?
 
 

To be done for (before!) the class of
Friday, 31 March


 


Prof.'s Question: (a) In what way is an electron like a rainbow`? (b) How does "phase entanglement" destroy "locality"? (c) Give some arguments for the "fictitious nature" of proxy waves. (d) What effect does von Neumann's result -  that it doesn't matter where the collapse of the wave function occurs - have on Everett's many worlds interpretation of quantum theory?
 
 


To be done for (before!) the class of
Monday, 3 April


 


Prof.'s Question: (a) Would David Bohm agree with Herbert's  statement "The quantum world is objective but objectless"? (b) What is a "delayed choice" experiment, and how does it influence your notion(s) of "reality"? (c) What is the relationship, if any, between "undivided wholeness" and Bohm's "neorealism" ( between Herbert's quantum reality #3 and #6)? (d) What is your personal choice for ultimate reality among the 8 "realities" presented by Herbert? Why?
 


To be done for (before!) the class of
Wednesday, 5 April


 


Prof.'s Question: (a) Joe tears a lottery ticket into two halves, each bearing the same number, and mails one of them to Jane, the other to Jill.  Since she knows the distribution of numbers  printed by the lottery, Jane knows the probability that Jill will receive a certain number, but as soon as she receives her letter, she knows with certainty what number Jill will receive.  How does this story differ from that of Einstein-Podolsky-Rosen? (b) What bearing do "hidden variables" have on the J-J-J story and on the E-P-R story?
 
 


To be done for (before!) the class of
Friday, 7 April


 


Prof.'s Question: How does Bell's Theorem and its experimental consequences go beyond the results of the Einstein-Podolsky-Rosen analysis of reality? What are the consequences of this difference?
 


To be done for (before!) the class of
Monday, 10 April


 


Prof.'s Question: (a) If reality is non-local, can we send information superluminally? How, or why not? (b) Are you a "phenomenolist"? Why or why not? (c) If quantum theory is someday replaced - perhaps by a psychologically and/or philosophically more acceptable theory - what happens to Bell's Inequality? (d) One might be able to describe a Spinoza type "clock-works universe" as a "counter CFD universe". How so (i.e., in what way does the existence of "free will" require CFD)? (e) Herbert says that there is only one random structure, i.e., there is no way to differentiate between different random sequences.  How then do you account for our ability to pick out  specific stars in the apparently random starry night sky?  (f) How does Herbert's statement preclude superluminal communication?
 


To be done for (before!) the class of
Wednesday, 12 April

Prof.'s Question:  (a) Why is it regarded as desirable that the ultimate constituents of matter have no size at all? (b) What is the difference between "bosons" and "fermions"? (c) What evidence do we have that the universe is primarily made up of matter and radiation (no anti-matter)?  Why is this a puzzle? (CPT Theorem = “charge conjugation” * ”parity inversion” * ”time reversal” invariance) (d) What are some of the differences between a classical field and a quantum field? (e) What is the relation between a “virtual particle” and the Heisenberg Uncertainty Relation?  How does this effect the range of forces between elementary particles?

To be done for (before!) the class of
Friday, 14 April

Prof.'s Question:  (a) Is the physical vacuum of modern physics devoid of physical activity?  What is its relation to the “ether”? (b) If a particle is “elementary”, how can it emit (decay into) other elementary particles?  (c) What is a "coupling constant"? Give some examples.(d) What field coupling is shared by all fermions? By all particles whether bosons or fermions?  (e) Is a “Feynman diagram” a picture of the motion of real particles?

To be done for (before!) the class of
Monday, 17 April
Prof.'s Question: (a) If there is no simpler form of reality underlying that of the "Standard Model", is reductionism still a valid approach to science? Why?  (b)  What are the constituents of the Standard model”?  (c) What’s the difference between leptons and hadrons (strongly interacting particles)?  (d)Different fields differ in having different masses of the associated particles and different coupling constants.  Are these independent differences?  Are these “constants” truly constant?

To be done for (before!) the class of
Wednesday, 19 April

Prof.'s Question:  What was the “big bang”?  How did it lead to the present universe?  What evidence do we have for its occurrence
 
 

To be done for (before!) the class of
Monday, 24 April

Prof.'s Question: (a) List and describe all of the physics revolutions that have been discussed in this class.  Why does each of these deserve the title "revolution"? (b) Can you think of any similar revolutions occuring outside of physics? (c) Are there any relations between the physics and non-physics revolutions?