Gelombang Bunyi
49
Gelombang Bunyi
• mendeskripsikan gejala dan ciri-ciri gelombang bunyi;
• menerapkan konsep dan prinsip gelombang bunyi dalam teknologi.
Setelah mempelajari bab ini, Anda harus mampu:
2A2D29?52632H2?82?5E?:2D2?A2252?H23E?H:E?:2 22?D6B2C2CE?H:D2?A2252?H23E?H:6B282;6?:C3E?H:6?;25:2?
5E?:2:?:=63:9O9:5EAP?5252A2D6?56?82B2?EC:2B6?2252?H2 A6B232D2?86=32?83E?H:H2?8C2A2:6D6=:?82?52+29E29
?52C:72DC:72D52?=2C:7:2C:86=32?83E?H:,=DB2C?:6BEA22? C2=29C2DE;6?:C3E?H:H2?852A2D5:A2?42B2?=696=6=2G2B6=32?8
3E?H:D6BC63ED36BA6B2?C63282:OA6?8:?5B2P6D:26=6=2G2BD6B32?8 A2522=292B:
6=2:?E=DB2C?:D6B52A2D;6?:C86=32?83E?H:=2:??H2,?DE 6?86D29E:=63:9=2?;EDD6?D2?8;6?:C;6?:C86=32?83E?H:C:72DC:72D
86=32?83E?H:52?76?6?276?6?2=2:??H2H2?836B2:D2?56?82? 86=32?83E?H:C6BD2A6?6B2A2??H252=2D6?=8:A6=2;2B:=292D6B:
A252323:?:C642B232:
menerapkan konsep dan prinsip gejala gelombang dalam menyelesaikan masalah.
Hasil yang harus Anda capai:
49
A. Sifat Dasar Gelombang Bunyi
B. Cepat Rambat Bunyi C. Unsur Bunyi dan
Pemanfaatan Gelombang Bunyi
D. Sifat-Sifat Gelombang Bunyi
E. Dawai dan Pipa Organa sebagai
Sumber Bunyi
F. Energi Gelombang Bunyi
Kelelawar ladam kuda horseshoe bat dapat memancarkan gelombang bunyi ultrasonik yang berfungsi sebagai pengindra ketika terbang pada malam hari.
Bab
3
Sumber: Fundamental of Physics, 2001
DIUNDUH DARI: WWW.BUKUPAKET.COM Sumber buku bse.kemdikbud.go.id
Mudah dan Aktif Belajar Fisika untuk Kelas XII
50
A. Sifat Dasar Gelombang Bunyi
A229?526?86D29E:ABC6CD6B;25:?H23E?H:25252C2B?H2 C6CE2DE H2?8 36B86D2B 252=29 CE36B 3E?H: E?H: C66B ?H2E
D6B56?82B 2B6?2 6A22? 3E=E3E=E 65E2 C2H2A?H2 H2?8 6:=:: 7B6E6?C:C6:D2B
IE?H:C66B;2?8B:D6B56?82B2:32D252?H2
86D2B2? 65E2 C2H2A?H2 H2?8 36B86C62? C642B2 D6BEC6?6BEC 6=32?8:?7B2C?:5:A2?42B2?=69C66BA2EC56?82?7B6E6?C:
C2?82DB6?5295:32G29
ID6D2A:2AE5:D2?82A=69A2ECH2?8 =2:?G2=2EAE?;2?82E2??H2B2DEC2?:=6D6B
6B365256?82?CE36BCE36B3E?H:D6BC63ED3E?H:A2522=2D2=2D EC:H2?852A2D:D256?82BD6B2CE86=32?82E5:C?:E?H:
H2?86=E2B52B:2=2DEC:36BC:72DD6B2DEBC69:?8825:?222?56?82? ?25252AE?3E?H:H2?8D:52D6B2DEB5:?222?56C29
6B92D:2? 3 252 8232B D6BC63ED D6B=:92D 86D2B2? =?46?86?892C:=2?86=32?83E?H:H2?86B232D6=2=E:65:2
E52B26?E;ED6=:?82H2?836BEA286=32?8=?8:DE5:?2= 25252C2B?H286=32?83E?H:52A2D6B232D5:65:E2A2AE?
6B92D:2? . 62AE2?65:EE?DE6?886D2B2?A2BD:6= 36B365236523292?25265:EH2?852A2D6B6523E?H::C2=?H22:B
6=32?83E?H:52A2D6?E?;E2?C:72DC:72DEE86=32?8 C6A6BD:52A2D6?82=2::?D6B76B6?C:5:7B2C:B67B2C:52?B6C?2?C:
?52;E8222?6A6=2;2B:A6B:CD:G2CEA6BAC:C:C6A6BD:CEA6BAC:C:5E2 86=32?8 3E?H: H2?8 64:= A6B36522? 7B6E6?C:?H2 C69:?882 6?8
92C:=2?3E?H:E2D=629C642B2A6B:5:H2?85:C63EDA6=2H2?82?3E?H: 6B52C2B2?2B29B232D?H2D6B2CE86=32?82A2293E?H::DE
82B?526292:?H2A6B92D:2?3
3
6?E?;E2?CE36B3E?H:36BEA286D2B2?63B2? 32C 5BE 6D2B2? C6=2AED H2?8 6BEA22? 56?HED 36B5:6?C: 5E2
5:A2?DE=2?C642B236BE=2?8E=2?8=6932D2CC6=2AEDC69:?882C6=2AED22? 36B86D2BC642B2A6B:5:6D:2C6=2AED36B86B26=E2B22?D6B;25:
A62A2D2?E52B25:56A2??H262A2D2? D6BC63ED6?H63232? D62?2?E52B236BD2329H2?85:C63ED526B29B2A2D2?2A2D2?36B86B2
6?;2E9:C6=2AED52=232D2C646A2D2?3E?H:2A2D2?52?B6?882?82? H2?8D6B36?DE52B:A2BD:6=A2BD:6=E52B2:B:A56?82?B2A2D2?52?
B6?882?82?86=32?8=?8:DE5:?2=A252C=:?:25:86=32?8=?8:DE 5:?2=6BEA22?C:72D52C2B86=32?83E?H:
. 6A2D232DE?H:636B2A2292?
A252E9E
L
+6 255
608+4 :B
:B=2ED =E:?:E
6C:52?2;2 6=2C
6=:E :5B86?
2HE6B2C ,52B2
Gambar 3.1
Gelombang bunyi dari lonceng yang bergetar
merambat melalui media udara sampai ke telinga.
Gambar 3.2
Getaran dari membran bas drum membuat partikel udara
merapat dan merenggang.
.62.,3+-1042.10608+-3,-0.41.41.3+-65.6-6.5+0
Tes Kompetensi Awal
6B52C2B2? CE36B?H2 3E?H: D6B2CE ;6?:C 86=32?82A2
A22986=32?83E?H:52A2D6?82=2:A=2B:C2C: A2H2?85:2CE556?82?2E5:C?::?7B2C?:
52?E=DB2C?: A2H2?85:2CE556?82?86252?82E?8
A22986=32?8H2?85:A2?42B2?A62?42BB25: D6B2CE86=32?8=?8:DE5:?2=
rapatan renggangan
x
tekanan udara
Sumber: Physics, 1995
DIUNDUH DARI: WWW.BUKUPAKET.COM Sumber buku bse.kemdikbud.go.id
Gelombang Bunyi
51
E?H:52A2DD6B56?82B;:286D2B2?52B:CE36B?H252A2D6B232D 9:?8826D6=:?8265:2B232D2??H252A2D36BEA2I2DA252DI2D42:B
52?I2D82C25:5:A6B=E2?65:EE?DE6?;2=2B2?3E?H:2C:9 :?82D29?52A6B:CD:G2D6?D2?83E?H:H2?852A2D6B232D6=2=E:C6ED2C
36?2?832C29H2?865E2E;E?8?H2D6B9E3E?82=6?8CECE56?82?32?DE2? CE2B2D62??52296?EBED?5252A2D293E?H:6B232D5:52=2
F2E,?DE6?86D29E:;2G232??H2=2E2?=292D:F:D2C36B:ED
Aktivitas Fisika 3.1
Kata Kunci
• gelombang bunyi • gelombang longitudinal
• gelombang infrasonik • gelombang audiosonik
• nada • desah
• pelayangan bunyi • ruang vakum
Gelombang longitudinal adalah gelombang yang arah getarnya
searah dengan arah rambatannya
Ingatlah
A229H2?85:2CE556?82?CE36B3E?H: 63ED2?C:72DC:72DH2?85::=::86=32?83E?H:
A2293E?H:52A2D6B232D5:BE2?892A2E52B2 6?82A2
6B52C2B2?2B2986D2B?H2D6B2CE86=32?8 2A2293E?H::DE
A229A6B36522?2?D2B2?25252?56C29
Tes Kompetensi Subbab
A
3,-0..6-6.5+0
B. Cepat Rambat Bunyi
