
350
.
, .
, ,
.
(. 4.18, )
1, .
.
2.
,
.
, , ,
.
l
1
= Z, (4.56)
– ;
Z – .
l = l
1
n = Zn, (4.57)
n – .
l v
v
– ).
,
Zn v
, (4.58)
.
. 4.18.
.
20–25 / .
70–75% .
(. 4.18, )
4, 3.