Post on 12-Jul-2020
Q
Q Q – Q
Q
– Q
Michael Faraday (UK)
Q = C V = k Q0 = k C0V0
k = C
C0
C =
QV
C
Gap
Gap
- e - e
- e - e
d
Q -Q
p = Qd
+
+ + + + + + + + + + + + + + + +
+
+
+ +
+
+
+
H 2O
E0
E0 = 0
E0
E0
Q -Q
p = Qd
+
d
P
n P
p = E
v
d n
S
S d
QP
d
- QP
QP
QP = d n S = P n S = P dS
QP
S
p = v d
P =p
v= d
P = N E
P = pii = 1
N
- QP
- QP = P dS
S
P dS
S
= Pdvv
= - P dvv
P = - P
n d
- P P
D = 0 E + P = 0 E + e 0 E = 0 1 + e E
r = 1 + e
D = E = 0 r
E = 1
0+ P = 1
0- P
0 E = - P
0 E + P = = D
P = N E P = e 0 E
S
0
- P
D = 0 r E = E
+ + + + + + + + + + + + + + + +
+
+ + + +
+
+ + + +
+
V
P
+ P
t
t
t
- t - t
- P
t - P
- t - P
- P P
E0 E0
E0
an
t - t
P - P
- P
0
t
0
E = t
0an
P
0an
E
E
1r
E
D = E= 0 r E
E r = 80
r = 1
r = 3.2
r 1
E0
E0 E0 1
r
D = 0 E + P = 0 r E P = 0 r E - 0 E= 0 r - 1 E
E = 1
0
D - P = D0 r
= 0 r 0
0
E dl = 0
D dS
S
= Q
upper
+side
+lower
= Q
A
B
+B
C
+C
D
+D
A
= 0
h 0
h 0
A B
C D
w
h dl
S
1
2
E1
E2
D2
D1
Dt1
Dn1
Dn2 Dt2
Et2
En2
En1 Et1
Dn1 S +
h2 L Dt1 + Dt2 - Dn2 S = s S
Dn1 - Dn2 = s
0
Et 1 = Et 2 Dn 1 = Dn 2
1 E n 1 = 2 E n 2
Dt 1
1= Dt 2
2
Et2 w +
h2 En2 ( B) + En1 (C)
- Et1 w -h
2 En1 (D) + En2 (A) = 0
Et2 - Et1 w = 0
Et 1 = Et 2
Dn 1 = Dn 2
D = E
D1 cos 1 = D2 cos 2
D1
1
sin 1 =D2
2
sin 2
tan 1
1
=tan 2
2
tan 1
tan 2
= 1
2
1
2
2
1
D1 = 1 E1
D2 = 2 E2
2 < 1if
1 < 2if
1 < 2
2 < 1
if 2 < 1
2 < 1
E2 < E1
if thenthen
1
1
2
2
E2 = Et 22 + En 2
2
D2 = Dn 22 + Dt 2
2
= D1 cos21 +
2
1
2
sin21
= E1 sin2
1 +1
2
2
cos21
1 < 2
1 < 2
E1
E2
2
1
E2
E1
2
1
E1 < E2
E E0 E0
0
0
r = 2
r = 1
r = 1
= 0 r
E0
1 = 0
1 = 45°
2
2 = 3 0
1
2
1
E1
E2
2
D = E
We = 1
2D E dv
v
0 = 0 r
Q
a
r > a
D = 0 r E=Q
4 r2ar
We = we dv
v
=1
2 0 r
Q4 r2
2
4 r 2 dra
=Q 2
8 0 r a
r
r
1r
we = D E
2=
D 2
2=
12 0 r
Q4 r2
2
D E
2 = E E2 =
E 2
2 =D 2
2
ab
Q
c
-Q
a < r < b = 0
= 0 r
D dS
S
= Dr 4 r2 = Q
Dr = 0 Er = Q
4 r 2
Dr = 0 r Er = Q
4 r 2
E = Er ar = Q
4 0 r2ar
E = Er ar = Q
4 0 rr2
ar
Cr
C= r
r
V = –
Q4 0 r 2 ar dr ar
b
a
= –Q dr
4 0 r 2b
a
=Q
4 0
1r b
a=
Q4 0
1a – 1
b
V =
Q4 0
1a – 1
b
Vr=
Q4 0 r
1a – 1
b
C =
QV
=4 0
1a – 1
b
C
r=
QV
r
=4 0 r
1a – 1
b
V
r=
V0
r
V0
r
V0 Q ' = r C0 V0
Q '
Q '
-Q '
Q ' V0
2=
CrV0
2
2 = r
C0 V02
2
r C0 V0 = Q '
Q0 = C0 V0 = C
rV
r= r C0
V0
r
Q0 Q'