Transcript Announcements 1/9/12

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Announcements 1/9/12
Prayer
Combination for walk-in lab optics room: 88542 (e0)
About my office hours: move time or move
location?
Reminder (“what you should already know”):
2
Review:
 ( A)  ( A)   A
 E 
Gauss’s Law
 B 
Gauss’s Law for B
 E 
Faraday’s Law
 B 
Ampere’s Law (partially correct)
Ampere’s Law example
E
1 q
1 qr
rˆ 
4e 0 r 2
4e 0 r 3
Reading Quiz
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The “continuity equation”, aka “equation of
continuity” is which of the following?
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a.   E 
e0
b.   B  0
c.
 B  0 J
E
d.   B  e 0 0
t

e.   J  
t
Maxwell’s fix to Ampere’s Law
E
1 q
1 qr
rˆ 
4e 0 r 2
4e 0 r 3
Maxwell’s Equations, Phys 220 form

E  dA 
qenclosed
closed
surface

e0
B  dA  0
Gauss’s Law
Gauss’s Law for B
closed
surface

closed
path

closed
path
dB
Ed  
dt
B  d  0 I enclosed
Faraday’s Law
d E
 0e 0
dt
www.physicssongs.org
units of current
Ampere’s Law
with Maxwell
correction
Maxwell’s Equations, Phys 441 form

E 
e0
Gauss’s Law
 B  0
Gauss’s Law for B
B
 E  
t
Faraday’s Law
E
  B  0 J  e 0 0
t
Ampere’s Law (with
Maxwell correction)
P&W P1.4 (due Thurs Jan 12): Memorize these four eqns
(and two others). There will be a quiz on Friday Jan 13!
Wave equation in free space
“And so to Maxwell the mystery was revealed—
he saw how light could move through empty space.
The changing B-field made the changing E-field,
and vice versa, all at the perfect pace!”