, (5,8)
ɝɞɟ
S
0
— ɤɪɭɬɢɡɧɚ ɩɪɨɯɨɞɧɨɣ ɯɚɪɚɤɬɟɪɢɫɬɢɤɢ ɜ ɥɢɧɟɣɧɨɦ ɪɟɠɢɦɟ. Ɍɨ ɟɫɬɶ
ɚɦɩɥɢɬɭɞɚ ɤɨɥɟɛɚɧɢɣ ɜɥɢɹɟɬ ɧɚ
S
1
ɩɨɫɪɟɞɫɬɜɨɦ ɢɡɦɟɧɟɧɢɹ ɭɝɥɚ ɨɬɫɟɱɤɢ
Θ
, ɱɬɨ
ɛɵɥɨ ɩɨɞɪɨɛɧɨ ɪɚɫɫɦɨɬɪɟɧɨ ɜ ɩɚɪɚɝɪɚɮɟ 1.5.
ɇɚ ɪɢɫ. 5.5 ɩɪɟɞɫɬɚɜɥɟɧɵ ɬɪɢ
ɜɨɡɦɨɠɧɵɯ ɜɚɪɢɚɧɬɚ ɡɚɜɢɫɢɦɨɫɬɢ
S
1
(U
ɜɯ
)
: 1) ɩɪɢ
E
ɫɦ
> E
′
, 2) ɩɪɢ
E
ɫɦ
= E
′
, 3) ɩɪɢ
E
ɫɦ
< E
′
. ȼ ɩɟɪɜɨɦ
ɫɥɭɱɚɟ ɢɦɟɟɬɫɹ ɭɱɚɫɬɨɤ ɥɢɧɟɣɧɨɝɨ
ɪɟɠɢɦɚ, ɜ ɤɨɬɨɪɨɦ
S
1
=
S
0
. ɉɪɢ ɩɨɹɜ-
ɥɟɧɢɢ ɨɬɫɟɱɤɢ ɭɝɨɥ
Θ
ɢɡɦɟɧɹɟɬɫɹ ɨɬ
π
ɞɨ
π/
2
ɩɪɢ
U
ɜɯ
→ ∞,
S
1
ɫɬɪɟɦɢɬɫɹ
ɤ
0,5S
0
, ɧɨ ɩɪɢ ɩɟɪɟɯɨɞɟ ɜ ɉɊ ɪɟɡɤɨ
ɩɚɞɚɟɬ. ȼɨ ɜɬɨɪɨɦ ɫɥɭɱɚɟ ɭɝɨɥ
ɨɬɫɟɱɤɢ
Θ
=
π
/ 2
, ɚ
S
1
=
0,5S
0
ɞɨ ɜɨɡ-
ɧɢɤɧɨɜɟɧɢɹ ɉɊ. ȼ ɬɪɟɬɶɟɦ ɫɥɭɱɚɟ
ɫɭɳɟɫɬɜɭɟɬ ɭɱɚɫɬɨɤ, ɝɞɟ
U
ɜɯ
<
|E
′
– E
ɫɦ
|
ɢ
S
1
=
0.
ɉɪɢ ɜɨɡɪɚɫɬɚɧɢɢ
U
ɜɯ
ɭɝɨɥ
Θ
ɢɡɦɟɧɹɟɬɫɹ ɨɬ 0 ɞɨ
π
/ 2
,
S
1
ɜɨɡɪɚɫɬɚɟɬ ɨɬ
0
ɞɨ
0,5S
0
, ɧɨ ɧɟ ɞɨɫɬɢɝɚɟɬ ɷɬɨɝɨ
ɡɧɚɱɟɧɢɹ, ɬɚɤ ɤɚɤ ɬɪɚɧɡɢɫɬɨɪ ɩɟɪɟɯɨɞɢɬ ɜ ɉɊ.
Ɋɟɲɟɧɢɟ ɭɪɚɜɧɟɧɢɹ (5.7) ɧɚɯɨɞɢɬɫɹ ɩɪɢ ɩɟɪɟɫɟɱɟɧɢɢ ɤɪɢɜɨɣ
S
1
(
U
ɜɯ
) ɫ
ɝɨɪɢɡɨɧɬɚɥɶɧɨɣ ɩɪɹɦɨɣ ɧɚ ɭɪɨɜɧɟ
1/R
ɭ
, ɝɞɟ ɞɥɹ ɤɪɚɬɤɨɫɬɢ ɩɪɢɧɹɬɨ ɨɛɨɡɧɚɱɟɧɢɟ
R
ɭ
=
k
ɨɫ
R
ɧ
. ɉɪɢ ɦɚɥɨɦ ɭɪɨɜɧɟ ɨɛɪɚɬɧɨɣ ɫɜɹɡɢ, ɤɨɝɞɚ
1/R
ɭ
>
S
0
, ɝɟɧɟɪɚɰɢɹ
ɧɟɜɨɡɦɨɠɧɚ. Ʉɨɝɞɚ
0,5S
0
<
1/R
ɭ
<
S
0
ɦɨɠɧɨ ɩɨɥɭɱɢɬɶ ɨɞɧɭ ɫɬɚɰɢɨɧɚɪɧɭɸ
ɬɨɱɤɭ a. Ⱥ ɞɥɹ ɤɪɢɜɨɣ 3) ɧɚ ɪɢɫ. 5.5 ɦɨɠɧɨ ɩɨɥɭɱɢɬɶ ɞɜɟ ɫɬɚɰɢɨɧɚɪɧɵɯ ɬɨɱɤɢ (b
ɢ c), ɟɫɥɢ
0
<
1/R
ɭ
<
0,5S
0
. Ʉ ɫɬɚɰɢɨɧɚɪɧɵɦ ɬɚɤɠɟ ɫɥɟɞɭɟɬ ɨɬɧɟɫɬɢ ɢ ɬɨɱɤɭ
ɩɨɤɨɹ
U
ɜɯ
=
0
.
ɇɟ ɜɫɟ ɩɨɥɭɱɟɧɧɵɟ ɫɬɚɰɢɨɧɚɪɧɵɟ ɬɨɱɤɢ ɹɜɥɹɸɬɫɹ ɭɫɬɨɣɱɢɜɵɦɢ. Ⱦɥɹ
ɩɪɢɦɟɪɚ ɪɚɫɫɦɨɬɪɢɦ ɬɨɱɤɭ b. ȿɫɥɢ ɩɨ ɤɚɤɢɦ-ɥɢɛɨ ɩɪɢɱɢɧɚɦ ɜɯɨɞɧɨɟ ɧɚɩɪɹ-
ɠɟɧɢɟ
U
ɜɯ
ɭɦɟɧɶɲɢɥɨɫɶ, ɬɨ ɭɦɟɧɶɲɚɟɬɫɹ
S
1
, ɚ ɷɬɨ ɩɪɢɜɨɞɢɬ ɤ ɭɦɟɧɶɲɟɧɢɸ
U
ɜɵɯ
. ɇɚɩɪɹɠɟɧɢɟ
U
ɜɵɯ
ɫɜɹɡɚɧɨ ɫ
U
ɜɯ
ɱɟɪɟɡ ɤɨɷɮɮɢɰɢɟɧɬ ɨɛɪɚɬɧɨɣ ɫɜɹɡɢ
U
ɜɯ
=
U
ɜɵɯ
k
ɨɫ
. Ɉɬɫɸɞɚ ɫɥɟɞɭɟɬ, ɱɬɨ ɨɛɪɚɬɧɚɹ ɫɜɹɡɶ ɩɨɞɞɟɪɠɢɜɚɟɬ ɩɪɨɰɟɫɫ
ɭɦɟɧɶɲɟɧɢɹ ɚɦɩɥɢɬɭɞɵ
U
ɜɯ
ɢ ɤɨɥɟɛɚɧɢɹ ɩɪɟɤɪɚɬɹɬɫɹ. ȿɫɥɢ, ɧɚɩɪɨɬɢɜ, ɚɦɩɥɢ-
ɬɭɞɚ
U
ɜɯ
ɜ ɬɨɱɤɟ b ɧɚɱɧɟɬ ɫɩɨɧɬɚɧɧɨ ɜɨɡɪɚɫɬɚɬɶ, ɬɨ ɨɛɪɚɬɧɚɹ ɫɜɹɡɶ ɛɭɞɟɬ
ɩɨɞɞɟɪɠɢɜɚɬɶ ɩɪɨɰɟɫɫ ɭɜɟɥɢɱɟɧɢɹ
U
ɜɯ
.
Ɋɚɫɫɭɠɞɚɹ ɚɧɚɥɨɝɢɱɧɵɦ ɨɛɪɚɡɨɦ, ɦɨɠɧɨ ɭɛɟɞɢɬɶɫɹ, ɱɬɨ ɨɛɪɚɬɧɚɹ ɫɜɹɡɶ
ɫɬɪɟɦɢɬɫɹ ɭɞɟɪɠɚɬɶ ɤɨɥɟɛɚɧɢɹ ɨɤɨɥɨ ɬɨɱɤɢ c. ɗɬɚ ɬɨɱɤɚ, ɜ ɨɬɥɢɱɢɟ ɨɬ ɬɨɱɤɢ b,
ɹɜɥɹɟɬɫɹ ɭɫɬɨɣɱɢɜɨɣ. Ɉɛɳɟɟ ɭɫɥɨɜɢɟ ɭɫɬɨɣɱɢɜɨɫɬɢ ɢɦɟɟɬ ɜɢɞ
S
1
S
0
ɇɊ
1/ R
ɭ1
a 1
2
S
0
/
2
b ɉɊ
3 c
|E
′
– E
ɫɦ
|
U
ɜɯ
Ɋɢɫ. 5.5. Ɂɚɜɢɫɢɦɨɫɬɶ ɫɪɟɞɧɟɣ ɤɪɭ-
ɬɢɡɧɵ
S
1
ɨɬ ɚɦɩɥɢɬɭɞɵ ɜɨɡɛɭɠɞɟɧɢɹ
1/ R
ɭ2