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
Wednesday, 19 April
To be done for (before!) the class of
Monday, 24 April