. 3
: : B=B1+B2, B1 , 1 1; 2 I 2.
B1 2 , :
=1+2. (1)
1 2 . 1 2 , , .
B=m0I/(2pr). (2)
(2), 1 2:
1=2=80 .
1- . B1 2 (.3, ); , (1). , , : 1 = - 80 , 2=80 .
(1) 1 B 2,
= 1 +2=0.
2- . 1 2 (. 3, ).
1 = 2 = 80 .
(1) B 1 2
= 1 + 2 = 160 .
3- . , , , (. 3, ). , 1 2.
(3)
(3) 1 2, B =113 .
3. , , , r 0 = 20 (. 4). I, , 30 , l 60 .
. , , --: dB dl (1)
(1), , a. dl da. . 4,
. . 4
dl (1):
dB
r , a . r ,
(2)
, , (2) a1 a2:
(3)
, A cos a2= cos a1. (3)
.
. 4
cos a1 (4),
∙ .
(5) :
4. I =50 a=2p/3. (. 5). d=5 .
. , . B1 2 ,
|
|
1 2, . . = 1 + 2. 2 . , , , d = 0([ dl,r ]=0).
1 , (3), 3:
,
r0 1 (. 6)
α1→0 ( ), α2=α==2π/3 (cos α2= cos (2π/3))=½. r 0 =d sin (π−α)= d sin(π/3)= .
=1 (2= 0),
1 . . 6 X ( ).
. 5 . 6
1.
:
5. R = 10 I =80 . A, =20 .
. :
dB [ dl,r ] ,
dB , Idl , - r.
. 7
dl - (. 7). d B .
,
dI d B : dB┴ d B ║ , . .
d B= d B^+ d B ½½.
, d B┴ d I , , () :
( d I r , , sina=1). ,
2π cos β R/r (. 7)
, :
( . 7) .
6. , . 8. R =10 . , I =80 A, .
. , =∑i. (. 9) (1 3), , (2) R.
B = B 1+ B 2+ B 3
B 1, 2 3 , , , .
. 8 . 9
1, 1=0
B=B2+B3
, 2 3 , :
|
|
=2+3.
2 , I:
2 , , ,
3, (3) 3:
2 3
:
7. l =2,5 , d =20 , I =1 . F .
. , , . , . , ( 1 I 2) .
F 1,2, , I 1, I 2. ( . 10), I 2. 1. B 1
(1)
, I 2 dl2
dl B 1,
(2)
(2) 1 (1),
. 10
F 1,2 ;
, I 1= I 2= I l2=l,
,
:
F 1,2 d F 1,2 (. 10) ( ) .
8. R= 10 (B =50 ). I =10 . F, , , .
. (. 11) d l .
. 11
Idl d F = I [dlB]. .
, , . 11. d F
i j (); dFx dFy d F .
F, , :
L , L.
(1)
. 11 ,
dF dl d l R α,
dFy (1) -π/2 +π/2 ( . 11):
, F ( j).
F:
, ():
:
9. =10, , max=6,5 . I 2. . .
|
|
. , ,
(1)
, α=π/2(sin α=l), pm=IS, (1)
, , S= πr 2,
(2)
(2),
=104 .
10. =2, N=100 , , 10 ·/. . , I= 1 α=60.
. . , , , :
M=0.
(. 12): M 1 , , 2 , , .
. 12
, (1)
M 1 + M 2=0
1 2 , ,
(2)
2 , M 1.
, pm=ISN=Ia2N, I ; S=a2 ; N , (2)
(3)
. 12 , α=π/2 φ, , sin α=cos φ. (3)
(4)
, ( , ),
φ .
(4) :
11. = 10 , I = 100 , = 1. A, , , : 1) φ1=90; 2) φ2= 0. .
.
(1)
, .
( =0), φ=0, . . m .
, , (1), . . ( φ ),
dA = Mdj (2)
(1) , = IS=Ia2, I , S=a2 ,
, :
(3)
1. φ1=900
(4)
, ():
(4) A1=l .
2. 2=3. , , 2 , (3) sin φ φ:
(5)
φ2 (. . 9)
|
|
Φ2=30=3·l,75·10-2 =0,0525 .
I, , φ2 (5) 2=1,37 .
12. , U =400 , B =1,5 . : 1) R ; 2) . .
. 1. , : F. ( .) , , , n : F=man. F n,
| e | uB sin a=mu2/R, (1)
, u, , , ; ; R ; a v ( v ^ B a = 90, sin a =l).
(1)
(2)
(2) mu :
(3)
, U, = | e | U. (3),