1. 30 . , ?
:
q1 = q2 = q3 = q4 = 30 = 30.10-9 .
_______________________________
q5 =?
. , , . ', , - , q1, . q1 , 6
(.6)
0, (1)
, , , , q1 q2 , q3, q4, q5;
= + .
, , q1 = q2 = q3 = q4 = q,
F2 = F4 = , (2)
F3 = , (3)
F5 = , (4)
a ;
r = a .
. 6, F3 F = . (1)
F + F3 - F5 = F2 +F3 -F5. (5)
г (5) (2) (4)
= 0.
q.
,
3.10-8 = 2,87. 10-8 .
, .
2. 2 -1 5 . , 6 4 .
:
q1 = 2
q2 = - 1
d = 5
r1 = 6
r2 = 4
____________
?
j ?
7
. ³ . . , (e = 1) q1 q2 :
E1 = , (1)
E2 = . (2)
.7. E
, (3)
a .
.7 , .
,
. (4)
r1, r2, d
cos b = (r12 + r22 - d2) / (2r1r2).
cos
cosb = .
Ѳ: q1 = 2.10-9 , q2 = -10-9 , r1 = 6.10-2 , r2 = 4.10-2 , 1/4pe0 = 9.109 /, e = 1.
(1), (2), (4), (5), :
E1 = B/,
E2 = B/.
2 q2 , , (.7).
.
, q1 q2, j1 j2, j = j1 + j2
|
|
. (5)
,
.
3. , 6 , 20/. , , , 1/3 .
:
R = 6
= 20 /
l = 2/3 R
___________
-? -?
. , , Y (.8). 8
' dl dq = dl. .
. , dq,
-, dl .
' d . , OY.
, (1)
dEY = d sin a.
r = R dl = R d ,
dEy= sin = sin d . (2)
ϳ (2) (1), 0 , 2
E= = . (3)
. , dq,
. (4)
(4)
.
l = 2 R / 3,
. (5)
Ѳ: t = 2.10-8 /, R = 6.10-2 , 1/4pe0 = 9.109 /, e = 1, e0 = 8,85.10-12 /.
(3) (5), :
E = /,
.
4. 1 , 20 /. 25 , 1 , , 3 .
:
R = 1 = 1.10-2
t = 20 / = 2.10-8 /
q = 25 = 2,5. 10-8
a1 = 1 = 1.10-2
a2 = 3 = 3.10-2
_____________________
-?
.
= q(j1 - j2).
j. , ,
= .
, , r1 r2
, (1)
r1 = a1 + R, r2 = a2 + R.
, ,
(2)
ϳ (2) (1),
ln
ln (3)
,
ln
.
.
Ѳ: e = 1; t = 2.10-8 /; q = 2,5.10-8 ; 1/2pe = 2,9 109 /. r2 r1 (3) , .
|
|
,
= 2,5.10-8.2,9.109.2. 10-8 = 6,2.10-6 .
5. , 30 /. 20 1 . , 30 , .
:
= 30 /
a = 20
R = 1
b = 30
_____________
DN -?
. , ( ), ,
(1)
cos ,
(.9). (>>R), . cos < E > < cos >
<E> <cos > <E> <cos > S,
S = R2.
< E > < cos > cos A, ,
S cos A =EA R2 cos A. (2)
.10 ,
cos A = cos(90 - ) =sin .
(2)
sin sin .
9
Ѳ: t = 3.10-8 /; e = 1; a = 0,2 ; R = 10-2 ; 1/2pe = 2,9.109 /.
,
B..
6. . 100 4 /. , , .
:
j1 = 100
1 = 4 / = 4.106 /c
2 = 2 / = 2.106 /c
___________________
j2 ?
. , W = = const,
(- j) .
, (1)
, 2 = 1/2,
. (2)
(1) (2),
.
Ѳ: 1 = 4.106 /; m = 9,1.10-31 ; = 1,6.10-19 .
,
= 66 .
. 㳿 ,
.
, = - (j1 - j2).
7. 50 . 200 2. ' 㳿 .
:
F = 50 = 5.10-2
S = 200 2 = 2.10-2 2
__________________
w -?
. ' 㳿
(1)
=s/ee0 ;
s .
ϳ (1),
(2)
. q = sS 1 = s / 2ee0, . , 䳺
(3)
s2 (3) (2),
w = F / S
Ѳ: F = 5.102 , S = 2.10-2 2.
,
/3.
8. ̳ , 600 , 5 3 . 200 2. : ) , ; ) .
|
|
:
U = 600
,
d1 = 5 = 5.10-3
d2 = 3 = 3.10‑ 3
S = 200 2 = 2.10-2 2
________________
? D ?
U 1? U2 ?
?
. D1n = D2n.
, , D1n = D1 D2n = D2.
D1 = D2 = D. (1)
, D = ee0, e0, (1)
e1E1 = e22 , (2)
1 E2 ;
e1 e2 .
г
U = U1 + U2 . (3)
, U1 = E1d1 U2 = 2d2. (3)
U = 1d1 + E2d2. (4)
(2) (4),
Ѳ: d1 = 5.10-3 ; d2 = 3.10-3 ; e1= 7; e2 = 3; e 0 = 8,85.10-12 /.
,
B/;
B/;
B;
B;
/2.
= , (5)
q = S . , ( , ( = D),
,
.
1.
,
q , t.
2. , S :
,
k , .
3.
;
l .
4. G :
, .
5.
,
0 t 0;
t ( );
.
4. ' :
.
'
,
R - ;
.
7. :
-
;
- ( = 0)
;
- ( = )
,
( - ) ;
... , ;
U ;
R ( );
... .
8. ʳ.
: , , ,
,
, .
: ,
,
- ;
R - ;
|
|
... - ;
, ;
k .
9. , t
.
10.
.
11. -
,
Q , t.
- , .
12. j, '
,
q .
13.
(;
;
τ ;
m .
14. -
,
' .
15. .
,
, Q;
k .
,
F (F = 96,5 /);
;
n .
'
, ;
t , .
16.
,
<υ> ;
.
17. , ,
,
Q ;
;
b+ b- ;
18.
,
, ' ;
d (0 =N/(Vt), N , t ;
V ' .