Transcript of modern physics - School of Physics

Modern Physics ZCT
104E/3
Lecturer in charge:
Yoon Tiem Leong (袁添亮)
Email: [email protected]
Room 115, School of Physics, USM, Tel:
653 3674
www.geocities.com/tlyoon
Or
www.fizik.usm.my/tlyoon/
teaching/
modernphysics.htm
Course Description
Physic
after 1900
special
theory of relativity, particle nature of
light and wave nature of matter, introductory
quantum theory of atoms and introductory
quantum mechanics.
Time
Planning
Contact hours
Maximum contact hours =
(2 x 7) weeks x (3x50) mins/week = 35
hours (ideally, but practically the number
of contact hours could be lesser due to
holidays)
 Out
of the 42 classes scheduled, 4 will be
allocated for tutorials
 Estimated lecture hours  32
Topics to be covered
-1 The program of physics
1 lecture 13 Nov 03 (Thu)
0 Special theory of Relativity
12 (or 10) lectures 14 Nov 03 (Frid) 1 Some preliminary wave physics
2 lectures
2 Particle properties of radiation
5 lectures
3 Wave properties of particles
3 lectures
4 Introductory quantum mechanics
4 lectures
5 Atomic models
5 lectures
Total =
32 (30) lectures (flexi)
 Problem
Sets (tutorial): 4 sets, download
them from the web
 Exams:
confirm)
Two tests, x-hour final exam (yet to
Grading
 Grading will be weighted: Midterm tests + 1
computer-based test, both contribute 30%,
while final exam will contribute 70% to the
total weight.
Textbooks
1) Kenneth Kane, Modern Physics, John. Wiley &
Sons, 2nd edition (August 1995) (required)
2) Modern Physics (Saunders Golden Sunburst Series)
International edition, by Raymond A. Serway,
Clement J. Moses, Curt A. Moyer
(required) (alternatively, volume two, physics for
scientists and engineers by Raymond A. Serway, third
edition, by the same publisher)
3) Introduction to the Structure of Matter: A Course
in Modern Physics, by John J. Brehm (Author),
William J. Mullin, John Wiley & Sons; (January 1989)
(advanced)
4) Elementary Modern Physics, by
Richard T. Widner and Robert L. Sells,
Allyn and Bacon Inc., third edition
5) Concepts of Modern Physics, Arthur
Beiser, McGraw-Hill; 6th edition
6) Physics, Cutnell and Johnson, John
Wiley & Sons (International Edition), 6th
edition (simple)
7) Quantum Physics of Atoms,
Molecules, Solids, Nuclei, and Particles
by Robert Eisberg, Robert Resnick, John
Wiley & Sons; 2nd edition 7)
8) Introduction to special relativity, by
Robert Resnick, John Wiley & sons
Course requirement (informal):

The students must be familiar with basic
knowledge in some necessary
mathematical tools such as calculus,
differential equations, Taylor and/or
binomial expansion

The students must have already equipped
with fundamental knowledge in Newtonian
mechanics

English
MAILING LIST
Everyone must send an email to
[email protected] so that I could maintain a list
of contact
Type your name in the “Subject”
Those who fail to do so have to bear the
responsibility if any information pertaining to
the lectures, e.g extra classes, change of venue
and timetable etc., fail to reach him/her
Downloads


http://www.geocities.com/tl
yoon/calander.htm
Password for lecture notes:
011103 (the date AB took over
as PM)

Tutorial sets

Consultation hours
- anytime (but please call first)
General Comments

intellectually intriguing and
somewhat counter-intuitive, must
prepare to think logically like
Einstein.

Learn the methodology of doing
‘real’ physics

 No
‘hafalan’ will work here –
understanding is absolutely mandatory
 Interactive learning is strongly encouraged
– emailing, Q&A on class, in private, by
phone, chat room on the web etc.
 Your feedback to improve the quality of the
lectures is welcomed
 Must read text – lecture note is not enough
1st lecture: The program of
Physics

The program of physics is to devise
concepts and laws that can help
understand the physical universe.

A law in physics is a precise
mathematical statement of a relation
that has been found by repeated
experiment to hold among physical
quantities and that reflects
persistent regularities in the
behaviour of the physical world.
"good" physical laws
 generality,
simplicity, precision, fit
experimental observations (e.g.
Newtonian Physics)
 New physics supplants old physics
beyond the domain of validity of old
physics (e.g. Special relativity vs.
Newtonian Physics)
 The
limits of physical theories: classical
physics, quantum physics, special
theory of relativity, relativistic quantum
mechanics (QFT), general theory of
relativity, statistical physics
 Quantum gravity





Classical physics = physics before 1900 –
thermodynamics, EM, classical mechanics
modern physics = the physics of the
twentieth century (after 1900)
This course is about Quantum physics - atomic
and nuclear structure, and
special theory of relativity – speed approaching
that of light
failure of classical physics gives rise to modern
physics
The 'architects' of modern physics
From specific to general

Usually we start from some known but specific
theory and try to generalise it
 a new (general) theory will yield the old
(restricted) theory as a special approximation
 E.g. when backtracking to your younger age,
the difficult math you learnt in the University
must reduce to that of simple arithmetic
knowledge that you learnt in primary school
 E.g. the relativity and quantum theories must
yield classical physics when applied to largescale objects moving at speeds much lower than
the speed of light
The correspondence principle
 Extrapolation
from known physics to more
general physics requires some “criteria”
that must be fulfilled by the `new theory’

Any new theory in physics, whatever its
character or details, must reduce to the well
established classical theory to which it
corresponds when it is applied under the
circumstances in which the less general
theory is known to hold.
Example
Special case: The parabola motion of
projectile on Earth is a special
case of the more general case of
elliptic motion of satellite around
the Earth
 General case: The mathematical
description of satellite has to
reduce to parabolic motion of
projectile on Earth surface when the
length scale reduces from that of
Earth size (~6000km) to that of a
short distance (say, ~ 100 m)

Another example

Ray optics and wave optics, both describing the
propagation of light
 Geometrical optics: only rectilinear propagation,
reflection, refraction, valid only when l /d -> 0
 wave (physical) optics - more general (diffraction,
interference, also rectilinear propagation), more
comprehensive, valid up to l  d
Limit (wave optics) =
l /d  0
ray optics
(no wave phenomena)
YOU MIGHT BE A PHYSICS MAJOR...
if you have no life - and you can PROVE it
mathematically.
if you enjoy pain.
if you know vector calculus but you can't remember
how to do long division.
if you chuckle whenever anyone says 'centrifugal
force.'
if you've actually used every single function on your
scientific calculator.
if you always do homework on Friday and Saturday
nights.
if you know how to integrate a chicken and can take
the derivative of water.
if you hesitate to look at something because you don't
want to break down its wave function.
if you have a pet named after a scientist.
if you laugh at jokes about mathematicians.
if the Humane society has you arrested because you
actually performed the Schrodinger's Cat experiment.
if you avoid doing anything because you don't want to
contribute to the eventual heat-death of the universe.
if you consider ANY non-science course 'easy.'
if the 'fun' centre of your brain has deteriorated from lack of
use.
if you'll assume that a 'horse' is a 'sphere' in order to make the
math easier.
if you understood more than five of these indicators.
if you make a hard copy of this list, and post it on your door.
If these indicators apply to you, there is good reason to suspect
that you might be classified as a physics major. I hope this
clears up any confusion