Medan Listrik, Potensial Listrik, dan Kapasitor
87
:DE?87=EC=:CDB:I2?86?63EC3:52?8A6BC68: C:C:4;:2E2D652?=:CDB:C636C2B
I2?82B29?I2 2
C6;2;2B56?82?3:52?8
3
D682=EBEC3:52?8 4
636?DECE5EDLD6B9252A3:52?8
-63E296=6DB?5:=6D22?5:AEC2DC63E296A:?8 =82 36BE2D2? ?682D:7
=6DB? D6BC63ED5:
A6B46A2D6?E;E6A:?8=82AC:D:75:562D?I2 C636C2BP
C :265E26A:?86:=::
B2A2D E2D2? I2?8 C22 D6?DE2? ?:=2: B2A2D E2D2??I2
6
P
O
8-
6
P
O
P
O
C. Energi Potensial Listrik dan Potensial Listrik
1. Energi Potensial Listrik
+6B92D:2?26
-63E29E2D2?E;:- 5:562D2?56?82?
E2D2?- :32D?I2D6B;25::?D6B2C:2?D2B2E2D2?-
52?- 36BEA2
82I24E=3I2?82B29?I2D=2 6?=2
?DE36BA:?52952B:AC:C: .
6AC:C:. E2D2?-
92BEC6=2E2?EC292
6C2B?I2EC292I2?8 92BEC5:=2E2?252=29C632?5:?856?82?36C2B?I282I2E=352?
A6BA:?5292??I2 O
.2?52?682D:76?E?;E2?EC2926=2G2?82I2E=3
:2EC292 I2?85:=2E2?-
6=2=E:A6BA:?5292?I2?8C2?82D64:=22EC292- 52A2D5:A6B=6956?82?42B2
O . .
. .
- - .
. .
- - .
. - -
. .
O -6CE2:56?82?567:?:C:?I2EC292252=29ABC6CDB2?C76B6?6B8:2D2E
36C2B?I2 A6BE3292? 6?6B8: 2D2E 52=2 36?DE 2D62D:C?I2 C6A6BD: 36B:ED
, ,
,
O 2A2D:D2C:AE=2?329G2A6BC222?6?6B8:AD6?C:2=5:CE2DE
D:D:252=29
,
- - .
O 6D6B2?82?
EC292=:CDB:;E=6 82I2E=3
?CD2?D2E=3P -
E2D2?E;: -
E2D2?CE36B . ;2B22?D2B2-
52?- +
– –
q
2
q
1
q
1
F
c
F
2 1
r
1
r
2
Gambar 4.16
Interaksi antara muatan q
1
dan q
2
.
r
DIUNDUH DARI: WWW.BUKUPAKET.COM Sumber buku bse.kemdikbud.go.id
Mudah dan Aktif Belajar Fisika untuk Kelas XII
88
2. Potensial Listrik
+D6?C:2==:CDB:252=2936C2B?I26?6B8:AD6?C:2==:CDB:A6BC2DE2? E2D2?
+25226
AD6?C:2==:CDB:I2?85::=::=69-
252=29 C63282:36B:ED
,
- - -
- - .
.
O -642B2EEA6BC222?AD6?C:2==:CDB:5:CE2DED:D:I2?836B;2B2.
52B:E2D2?CE36B252=29 .
O :2E2D2?=:CDB:I2?86?82:32D2?E?4E=?I2AD6?C:2==:CDB:
;E=29?I2=63:952B:C2DEAD6?C:2==:CDB:5:C63E29D:D:6BEA22? ;E=292=;232BAD6?C:2=D6B9252AC6D:2AE2D2?=:CDB:
6C2B?I2E2D2?
AD6?C:2=5:D:D:,I2?85:C63232?=69E2D2?D:D:- -
- 252=29
,
- .
O +6B92D:2?26
:292?I2252E2D2?AD6?C:2==:CDB:
5:D:D:+252=29
,
- - -
. .
. O
3. Hubungan Usaha dan Beda Potensial Listrik
+6B92D:2?26
C292I2?85:=2E2?E?DE6:?5292? E2D2?-
52B:AC:C:. 6AC:C:.
52B:2B29E2D2?252=29
, ,
,
- - .
.
- .
.
- O
56?82? O
252=293652AD6?C:2==:CDB:2?D2B2D:D:
52?D:D:
Gambar 4.17
Potensial listrik oleh 3 muatan, q
1
, q
2
, q
3
di titik P. P
r
3
+
q
3
–
q
2
+
q
1
r
2
r
1
Gambar 4.18
Muatan q, bergerak dari titik 1 ke titik 2 dipengaruhi muatan Q.
r
2
r
1
2
1
-63E29E2D2?AC:D:7-
P
O
5:86B22?6?E;EC63E29:?D:2DI2?8 36BE2D2?
2B2A:C292G2=65E2A2BD:6=D6BC63ED252=29P
O
52?;2B2 A:C2929:B?I2252=29
P
O
:2EC292I2?85:A6B=E2?E?DE6:?5292? P
O
D6?DE2?E2D2?:?D:2DD6BC63ED :
:6D29E: -
P
O
. P
O
. P
O
P
O
Contoh
4.9
Q
q
DIUNDUH DARI: WWW.BUKUPAKET.COM Sumber buku bse.kemdikbud.go.id
Medan Listrik, Potensial Listrik, dan Kapasitor
89
-68:D:82
C:E C:E5:56?82?
452?4
-63E29E2D2? =:CDB:-O
O
22?5:A:?5292?52B:D:D:6D:D:I2?8D6B=6D2A252 A6BD6?8292?
:2E2D2?-
O
52?E2D2?- O
O
2?882A6925:B2? -D:5236BA6?82BE9D6B9252AAD6?C:2=5:D6?DE2?=29
2
AD6?C:2=5: =29-
52?- 3
AD6?C:2=5:
=29- 52?-
4
EC292I2?85:A6B=E2?E?DE6:?5292?E2D2?-52B:6 :
:6D29E:-
O
- O
O
-O
O
4 2
+D6?C:2==:CDB:5:2:32D-
52?- 252=29
- -
P F=D
3
+D6?C:2==:CDB:5:2:32DE2D2?- 52?-
=692B6?2- 6-
52?
22 O
C69:?882 O
4
C292E?DE6:?5292?E2D2?252=29 -
O O
O
O0P
O
;E=6
Tantangan
untuk Anda
Hitunglah usaha yang diperlukan untuk memindahkan muatan positif
yang besarnya 10 C dari suatu titik yang potensialnya 10 V ke suatu titik
yang potensialnya 60 V.
56?82?6723
5:A6B=69 -
. .
P
O
P P
O
P
O
25:E2D2?:?D:2D252=29P
O
Contoh
4.10
A B
C
D 10 cm
6 cm 4 cm
4 cm
4. Hukum Kekekalan Energi Mekanik dalam Medan Listrik
