10 magnetism of matter 磁 性 electromagnetic waves 電磁 波 how can a clay-walled kiln reveal...
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10 Magnetism of Matter 磁 性Electromagnetic Waves 電磁波
How can a clay-walled kiln reveal Earth’s magnetic field of the past?
10-2.7 Find B(r)
R)r(for 2
)(2
R)r(for 2
)(2
200
200
200
00
200
200
00
dt
dE
r
RB
dt
dERER
dt
drB
dt
dErB
dt
dErEr
dt
drB
dt
dsdB E
10-2.8 Displacement Current
0 0 0
0
0 , 0
+
+
Eenc
Ed
d enc enc
dB ds i
dtd
idt
B ds i i
10-2.9 Maxwell’s Equations
10-3 Electromagnetic Waves
The oscillating E and B FieldsA Most Curious Wave –The ether ( 以太 )
)sin(
)sin(
tkxBB
tkxEE
m
m
34-3 The Traveling Electromagnetic Wave
hdE
EhhdEEsdE
dt
dsdE
)(
• The induced electric field:
dt
dB
dx
dE
dt
dBhdxhdE
dt
dBhdx
dt
dhdxB B
B
,
),)((
hdE
EhhdEEsdE
dt
dsdE
)(
cB
E
tkxBtkxkE
tkxBt
B
tkxkEx
Et
B
x
E
dt
dB
dx
dE
m
m
mm
m
m
)cos()cos(
)cos(
)cos(
․The induced magnetic field:
hdB
BhhdBBsdB
dt
dsdB E
)(
00
000000
00
0000
1c ,
1
)/(
1
)cos()cos(
)(
),)((
ckB
E
tkxkxkBt
E
t
B
dt
dEhdxhdB
dt
dEhdx
dt
dhdxE
m
m
m
EE
10-3.3.1 Radiation Pressure․ Momentum Gain of an Object
)reflection (total 2
)absorption (total
c
Up
c
Up
Momentum change
energy change
․The Force Exerted by Radiation
)reflection (total 2
2
)absorption (total
c
Ip
c
IAF
c
Ip
c
IAF
c
tIA
c
UptIAU
t
pF
r
r
mGMc
PRFF
r
RGM
r
mGMF
cr
RP
c
RIF
c
IAF
r
PI
S
Sgr
SSg
Sr
rS
7
2
3
2
2
22
2
107.116
33
4
4
4
․The size of comet particles