kfe51_grapti_ergasia_6_2014_15_LYSEIS
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51 4", "
1. 10 B=k z x , k . , , , yz .
:
. 13.11 Feynman :d F=I d lB ,
d l . :
FAB=I (a y)B(z=a2)=a I y(ak
2x )=a
2 k I2
z
F=I (a y )B(z=a2)=a I y(ak
2x)=a
2 k I2
z
d F=I (dz z )B(z )=I(dz z )(k z x)=( I k y) zdz F= a/2
a /2
d F=( I k y) a /2
a/2
z dz=0
.
F=0 , :F=F+ F=a
2 k I z
2. 10 , , . ', u ( ) .
: ' 13.35 Feynman /:
x
y
z
A B
-
x '= ( I xu ) ,
'= ( uc2
I x).
, , x=0 , : x '= u ,
'= .
' ( Gauss, 5-5 Feynman):
E '= '20
1r '=
201r '
,
r ' '. Ampere ( 13-5 Feynman):
B '=0
2 r 'I x '=
02
u r '
.
3. 10 =0.01 , . 0. 1/e . Cu=5.96x107 S/m Cu=8.96 g/cm3 . L R=L/ (A ) .
: . := 2cos , =t
. (emf) :
emf=ddt
=B 2sint=I R
I=B 2
Rsint
,
R . :
P= I 2R=B2242
Rsin2t = B
22 42
2 R.
:
=12I 2 ,
B
-
.
=m a2
2, m .
, :d E kind t
+P=0 ddt( 14ma22)+B
22 42
2R=0
ddt
=B22a2
mR
=0et / , = mR
B22a2
.
1/e . m, R, : . :m=2 ,
R=2 A
.
:
=2 2
AB2 2a2
=4 B2
=48960
0.0125.96107=6 s .
4. 10 , . z . V=V 0 cos t , . D
-
z(I )=V 0D
cost ,
V . Maxwell ( Ampere ) () :
LBd l=0 0
S
E t
d S , (1)
. B(I )=B(I ) . :
(1)2 ( )=0 0 2(V 0D sint )
( )=0 0V 0
2D sint ,
-
B( II)d l=0 , (-) z . B(I )=B( I) , , () , :
2 ()=0
( )=0 0R
2V 02D
sint. (5)
(2),(4),(5) :
()( )=0 0V 0sin t
2D (2R2) =(4) 0 j() .
Ampere, , .
5. 10 xy , . L 1, L 2. . .
: :
= + = 1 z 2 z=L2 1 z (
L2)
2
2 z
=L2(I 1
4I 2) z
,
( 14.34 Feynman):
x
y
I1
I2
(I)
z
(II)
, j
B(I )
B(II )
-
A=04
rr2
=0 L
2
4 r 2( I 1
4I 2) zr
A=0 L
2
4 r2( I 1
4I2) z(x x+ y y+z z )=
0L2
4 r2( I 1
4I 2)( y x+x y )
,
r=x x+ y y+z x .
6. 10 R xy , (0,0,0) . z . .
: dt udt . dq=udt I=u ,
u :u=R .
=R . := z= R
2 R z= R3 z . ( 14.34 Feynman):
A=04
rr2
=04
R3 zrr2
A=0 R
3
4 r2(cos rsin )r=
0 R3
4 r2(sin) r
A=0 R
3
4 r2(sin )()=
0 R3
4 r2sin
,
z=cos rsin .
7. 10 R z . :B= 2 ,
, z . ) , J , .) A=A z( ) z , A z() .
:() :
-
B=0 J J=10B .
:
J= 10 [( 1 B z B z ) +(B z B z ) + 1 ((B) B ) z ]
J= 10
1(B)
z= 10
1( 3)
z=3 0
z
.
() ( ):
A=B= 2
A z
= 2
A z()= 2d =C 3
3
,
C .
8. 10 (n=1.5). 0 90 10 .
: 33.1 Feynman 33.3 33.4 . / , , : / 0=cos
2 R+sin2R .
/ , :
/ 0=cos2R+sin
2R=12(R+R ) .
33.3 33.4 Snell:
R=sin2(i t)sin2(i+t)
R=tan2(i t)tan2(i+t)
sini=nsin tt=sin1( 2
3sin i)
,
i:
-
i (o)
0 0.04
10 0.040015
20 0.04027
30 0.0415
40 0.0457
50 0.0577
60 0.0892
70 0.171
80 0.388
90 1.0
9. 10 . , R, x , . . ) , .) u .
:
() Ampere ( 13-5 Feynman):
B=0 2
1r
,
r . ( ), dr, r ( ):
I
x
0 10 20 30 40 50 60 70 80 900
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
i ()
I
x
r
dru
I
-
d=(r )adr=0 2
1radr .
r=x r=x+ :
= d=x
x +a 0 2
1radr=
0 a2 x
x+a drr=0 a2
ln(1+ ax) .
() :
emf=ddt
= ddt ( 0 a2 ln(1+ ax ))=0 a2 ddt ln(1+ ax )
emf=0 a
2dxdt
ddx
ln(1+ ax)=
0 au2 (a /x
2
1+ ax )
emf=0 a
2u2 x (x+a)
.
R, :
R=0 a
2u2 x (x+a)
=0 a
2u2 R x (x+a)
.
Lenz .
10. 10 ( ), . L R. I1(t )=I 10cost , 2(t ) .
:
2 :
emf 2=LdI2dt
MdI 1dt
=R I2
LdI 2dt
+R I 2=MdI 1dt
=M ddt( I10 cost )
LdI 2dt
+R I 2=M I 10 sint (1)
. (1) . :2=20 cos(t+) , (2)
20 . (2) (1) :
~ 1
2
-
L 20 sin(t+)+R I 20cos (t+)= 10 sintL 20(sint cos+cost sin)+R I 20(cost cossint sin)=10 sint
(L 20cos +RI 20 sin+ 10)sint+(R I 20cos L 20sin)cost=0.
sint cost , :
RI 20 cos=L 20 sin tan=RL
(3)
L 20cos +RI 20 sin+ 10=0
L 20+R I20 tan+ 10
cos=0 (3)
L 20+ I 20R2
L+
10cos
=0
(4)
, (3) :
cos= LR2+L22
.
(4) :
L 20+ I 20R2
L= 10
R2+L22L
=0
I 20= 10M
R2+L22.
, , (1) :
I2(t )= 10M
R2+L22cos(t+)+C etR /L , tan= R
L,
2,
C .
: ( ), , (2) (1) (1) (1). =L. , , .