gelombang bunyi

1. Kelelawar ladam kuda (horseshoe bat) dapat memancarkan gelombang bunyi
ultrasonik yang berfungsi sebagai pengindra ketika terbang pada malam hari.
Gelombang Bunyi 49
Gelombang Bunyi
Hasil yang harus Anda capai:
menerapkan konsep dan prinsip gejala gelombang dalam menyelesaikan
masalah.
Setelah mempelajari bab ini, Anda harus mampu:
• mendeskripsikan gejala dan ciri-ciri gelombang bunyi;
• menerapkan konsep dan prinsip gelombang bunyi dalam teknologi.
2A2D29 ?52 632H2?82? 5E?:2 D2?A2 252?H2 3E?H: E?:2
22? D6B2C2 CE?H: D2?A2 252?H2 3E?H: 6B282 ;6?:C 3E?H: 6?;25:2?
5E?:2:?:=63:9O9:5EAP?5252A2D6?56?82B2?EC:2B6?2252?H2
A6B232D2? 86=@32?8 3E?H: H2?8 C2A2: 6 D6=:?82 ?52 +29E29
?52 C:72DC:72D 52? =2C:7:2C: 86=@32?8 3E?H: ,=DB2C@?: 6BEA22?
C2=29C2DE;6?:C3E?H:H2?852A2D5:A2?42B2?@=696=6=2G2B6=@32?8
3E?H: D6BC63ED 36BA6B2? C63282: OA6?8:?5B2P 6D:2 6=6=2G2B D6B32?8
A252 2=2 92B:
*6=2:? E=DB2C@?: D6B52A2D ;6?:C 86=@32?8 3E?H: =2:??H2 ,?DE
6?86D29E: =63:9 =2?;ED D6?D2?8 ;6?:C;6?:C 86=@32?8 3E?H: C:72DC:72D
86=@32?83E?H:52?76?@6?276?@6?2=2:??H2H2?836B2:D2?56?82?
86=@32?8 3E?H: C6BD2 A6?6B2A2??H2 52=2 D6?@=@8: A6=2;2B:=29 2D6B:
A252 323 :?: C642B2 32:
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
Bab
3
Sumber: Fundamental of Physics, 2001

2. Tes Kompetensi Awal
'$'.6//'/2'.#,#3+-104'2'.1/$#0)608+-'3,#-#0.#*41#.41#.$'3+-65#.#/$6-6.#5+*#0
6B52C2B2? CE36B?H2 3E?H: D6B2CE ;6?:C

3. A22986=@32?83E?H:52A2D6?82=2:A@=2B:C2C:
A2H2?85:2CE556?82?2E5:@C@?::?7B2C@?:
A. Sifat Dasar Gelombang Bunyi
A229 ?52 6?86D29E: AB@C6C D6B;25:?H2 3E?H: (252 52C2B?H2
C6CE2DE H2?8 36B86D2B 252=29 CE36B 3E?H: E?H: C66@B ?H2E
D6B56?82B 2B6?2 6A22? 3E=E3E=E 65E2 C2H2A?H2 H2?8 6:=::
7B6E6?C: C6:D2B
I E?H: C66@B ;2?8B: D6B56?82B 2:32D 252?H2
86D2B2? 65E2 C2H2A?H2 H2?8 36B86C62? C642B2 D6BEC6?6BEC
6=@32?8 :?7B2C@?: 5:A2?42B2? @=69 C66@B A2EC 56?82? 7B6E6?C:
C2?82D B6?529 5: 32G29

4. I D6D2A: 2AE 5:D2?82A @=69 A2EC H2?8
=2:? G2=2EAE? ;2?82E2??H2 B2DEC2? :=@6D6B
6B3652 56?82? CE36BCE36B 3E?H: D6BC63ED 3E?H: A252 2=2D2=2D
EC: H2?8 52A2D :D2 56?82B D6B2CE 86=@32?8 2E5:@C@?: E?H:
H2?8 6=E2B 52B: 2=2D EC: 36BC:72D D6B2DEB C69:?882 5:?222? 56?82?
?252 52AE? 3E?H: H2?8 D:52 D6B2DEB 5:?222? 56C29
(6B92D:2? #/$#3 (252 8232B D6BC63ED D6B=:92D 86D2B2?
=@?46?8 6?892C:=2? 86=@32?8 3E?H: H2?8 6B232D 6=2=E: 65:2
E52B2 6?E;E D6=:?82 H2?8 36BEA2 86=@32?8 =@?8:DE5:?2=
(25252C2B?H286=@32?83E?H:52A2D6B232D5:65:E2A2AE?
(6B92D:2? #$'. 62AE2? 65:E E?DE 6?886D2B2? A2BD:6=
36B36523652 3292? 252 65:E H2?8 52A2D 6B652 3E?H: :C2=?H2 2:B
6=@32?8 3E?H: 52A2D 6?E?;E2? C:72DC:72D EE 86=@32?8
C6A6BD: 52A2D 6?82=2: :?D6B76B6?C: 5:7B2C: B67B2C: 52? B6C@?2?C:
?52;E8222?6A6=2;2B:A6B:CD:G2CEA6BA@C:C:C6A6BD:CEA6BA@C: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 ?52 6292:?H2 A6B92D:2? #/$#3
#/$#3
6?E?;E2? CE36B 3E?H: 36BEA2 86D2B2? 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?
36B86D2B C642B2 A6B:@5: #6D:2 C6=2AED 36B86B2 6=E2B 22? D6B;25:
A62A2D2? E52B2 5: 56A2??H2 (62A2D2? D6BC63ED 6?H63232?
D62?2? E52B2 36BD2329 H2?8 5:C63ED 526B29 B2A2D2? )2A2D2? 36B86B2
6?;2E9: C6=2AED 52=2 32D2C 646A2D2? 3E?H: )2A2D2? 52? B6?882?82?
H2?8 D6B36?DE 52B: A2BD:6=A2BD:6= E52B2 :B:A 56?82? B2A2D2? 52?
B6?882?82? 86=@32?8 =@?8:DE5:?2= A252 C=:?: 25: 86=@32?8 =@?8:DE
5:?2= 6BEA22? C:72D 52C2B 86=@32?8 3E?H:
86=@32?82A2
Gambar 3.1
52?E=DB2C@?:
Gelombang bunyi dari
lonceng yang bergetar
merambat melalui media
udara sampai ke telinga.
#$'.
6A2D)232DE?H:636B2A2292?
A252*E9E

5. L
#/##*#0
'+6/
'2#5#/$#5
608+/4
:B
:B=2ED
=E:?:E
6C:52?2;2
6=2C
6=:E
:5B@86?
#2HE6B2C
,52B2
Gambar 3.2
Getaran dari membran bas
drum membuat partikel udara
merapat dan merenggang.
50 Mudah dan Aktif Belajar Fisika untuk Kelas XII
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

6. Ingatlah
Gelombang longitudinal adalah
gelombang yang arah getarnya
searah dengan arah rambatannya
Gelombang Bunyi 51
E?H: 52A2D D6B56?82B ;:2 86D2B2? 52B: CE36B?H2 52A2D 6B232D
9:?882 6 D6=:?82 %65:2 B232D2??H2 52A2D 36BEA2 I2D A252D I2D 42:B
52? I2D 82C 25: 5:A6B=E2? 65:E E?DE 6?;2=2B2? 3E?H: %2C:9
:?82D29?52A6B:CD:G2D6?D2?83E?H:H2?8 52A2D6B232D6=2=E:C6ED2C
36?2?8 32C29 H2?8 65E2 E;E?8?H2 D6B9E3E?8 2=6?8 CECE 56?82? 32?DE2?
CE2B2D62??52296?EBED?5252A2D293E?H:6B232D5:52=2
F2E ,?DE 6?86D29E: ;2G232??H2 =2E2?=29 2D:F:D2C 36B:ED
Aktivitas Fisika 3.1
Kata Kunci
• gelombang bunyi
• gelombang longitudinal
• gelombang infrasonik
• gelombang audiosonik
• nada
• desah
• pelayangan bunyi
• ruang vakum
A2 H2?8 52A2D ?52 C:AE=2? 52B: 2D:F:D2C D6BC63ED %6?82A2
6D:2 E52B2 5: 52=2 D23E?8 5::C2A =226=222? 3E?H: ;2 G66B
D6BC63ED D:52 D6B56?82B 2= D6BC63ED 63ED:2? 329G2 86=@32?8
3E?H: 66B=E2? 65:E E?DE 6B232D
A229H2?85:2CE556?82?CE36B3E?H:

7. *63ED2?C:72DC:72DH2?85::=::86=@32?83E?H:
A2293E?H:52A2D6B232D5:BE2?892A2E52B2
%6?82A2
6B52C2B2? 2B29 86D2B?H2 D6B2CE 86=@32?8
2A2293E?H::DE
A229A6B36522?2?D2B2?25252?56C29
Tes Kompetensi Subbab A
'3,#-#0.#*#.#/$6-6.#5+*#0
B. Cepat Rambat Bunyi
6A2D B232D 3E?H: D:52 36B82?DE?8 A252 D62?2? E52B2 25: ;:2
D6B;25:A6BE3292?D62?2?E52B246A2DB232D3E?H:D:5236BE3296A2D
B232D3E?H:36B82?DE?8A252CE9E*62:?D:?88:CE9EE52B2C62:?
36C2B46A2DA6B232D2?3E?H::526B29A68E?E?82?46A2DB232D3E?H:
=63:9 =232D 52B:A252 46A2D B232D 3E?H: 5: 2G2C2? A2?D2: : E52B2
46A2DB232D3E?H:36B82?DE?8A252;6?:CA2BD:6=H2?8636?DEE52B2
D6BC63ED (6BC222??H2 52A2D 5:DE=:C2? C63282: 36B:ED
$
N
Tugas Anda 3.1
Apakah bunyi termasuk gelombang
elektromagnetik? Sebutkan alasan-alasan
yang mendasari jawaban Anda
tersebut.
Bunyi dalam Ruang Vakum
Tujuan Percobaan
Menyelidiki apakah bunyi dapat merambat melalui
ruang hampa.
Alat-Alat Percobaan
1. Jam weker
2. Tabung hampa udara (vakum)
Langkah-Langkah Percobaan
1. Bunyikan jam weker tanpa ditutup oleh tabung
vakum.
2. Tutup jam weker dengan tabung vakum. Amati
yang terdengar dari jam weker tersebut.
3. Gunakan sebuah pengisap untuk mengisap udara
dalam tabung vakum secara perlahan-lahan.
4. Amati perubahan intensitas bunyi jam weker tersebut.

8. #6D6B2?82?
@?CD2?D2 $2A=246
D6D2A2?EE82C
@=#
CE9E ED=2 82C 6=F:?
2CC2 @=6E= 82C 8B2 @=
6A2DB232D3E?H:52=2I2DA252D5:D6?DE2?@=69@5E=EC.@E?852?
2CC2 ;6?:C I2D D6BC63ED (6BC222??H2 52A2D 5:DE=:C2? C63282: 36B:ED
Contoh 3.1
$
2?5:?82?646A2D2?3E?H:52=22=E:?:E52?2:B;:2@5E=EC.@E?8E?DE
2=E:?:E
Q

9. @5E=ECE=2:B

10. Q

11. 52?646A2D2?
2:B
8
#7#$
:6D29E:
Q

12. 8

13. Q

14. 8
$
$

15. 8
Ingatlah
Pembahasan Soal
vt v =
RT
RT
M
Contoh 3.2
52 Mudah dan Aktif Belajar Fisika untuk Kelas XII

17. 8

18. C 4
#646A2D2?3E?H:5:2:BD6B?H2D2=63:964:=52B:A252646A2D2?3E?H:52=2
2=E:?:E 2= D6BC63ED 5:C63232? 42:B2? =63:9 @AB6C:36= =63:9 E529
36BE32936?DE5:32?5:?82?56?82?I2DA252D@5E=ECE=42:B2?=63:9
64:=5:32?5:?82?56?82?@5E=EC.@E?8E?DEI2DA252D
Cepat rambat bunyi di udara
bergantung pada suhu udara.
Tugas Anda 3.2
Bandingkan nilai cepat rambat bunyi
di udara yang Anda dapatkan dari
percobaan dan dari buku referensi.
Jika ada perbedaan, berikan analisis
Anda mengenai hal tersebut.
Iskandar mendengarkan kembali
suaranya sebagai gema dari sebuah
tebing setelah waktu 4 detik. Jika
adalah perbandingan panas jenis
udara pada tekanan dan suhu
konstan, serta Iskandar mengetahui
bahwa suhu saat itu T kelvin dan
massa molekul relatif udara M,
Iskandar dapat menentukan jarak
tebing menurut persamaan ....
a.
RT
M
d. 6
RT
M
b. 2
RT
M
e. 8 RT
M
c. 4
RT
M
UMPTN 1996
Pembahasan:
d =
2
RT
M
d =
2
t
M =
4
2
6A2DB232D86=@32?83E?H:5:E52B2A252CE9E

19. L252=29
C:2CE9E
E52B2?2:6?;25:
LD6?DE2?46A2DB232D86=@32?83E?H:D6BC63ED
#7#$
#6D:2 CE9E E52B2 ?2: 646A2D2? 3E?H: 22? C62:? 36BD2329 2= D6BC63ED
5:C63232?86B22?86B22?@=6E=E52B2H2?86B232D2?3E?H:36BD232946A2D
:6D29E:

20. #

21. #
$
C
N

22. #6D6B2?82?
@5E=EC .@E?8 I2D A252D

23. 2CC2 ;6?:C I2D A252D 8
:52=2I2D42:B46A2DB232D3E?H:5:D6?DE2?@=69@5E=ECE=
52? 6B2A2D2? 2CC2 ;6?:C 42:B2? D6BC63ED (6BC222??H2 52A2D
5:DE=:C2? C63282: 36B:ED
$
N
#6D6B2?82?
@5E=EC E=

24. 2CC2 ;6?:C I2D 42:B 8
= 2
RT
M
Jawaban: b

25. Kata Kunci
• cepat rambat bunyi
• konstanta Laplace
• modulus Young
• modulus Bulk
2
3
Gelombang Bunyi 53
$

26. $
$

27. $

28. C
25:46A2DB232D3E?H:36BD23296?;25:

29. C
Tes Kompetensi Subbab B
'3,#-#0.#*#.#/$6-6.#5+*#0
+6?DE2?646A2D2?3E?H:52=282C2B3@?5:@C:52
A252 CE9E
L ;:2 36B2D@=6E='

30. 52?

31. 6A2DB232D3E?H:A252CE9ELC2256?82?

32. C
+6?DE2?46A2DB232D3E?H:A252CE9E
L
6A2DB232D3E?H:52=282C'

33. 252=29
C
6B2A22946A2DB232D?H252=282C'

34. A252CE9EH2?8C22
:DE?846A2DB232D3E?H:A252C632D2?836C:
Q

35. 52? 8B2 4
6B2A2 2=: =:A2D29 646A2D2? 3E?H: A252 32;2 5:
32?5:?82?56?82?646A2D2?3E?H:A2522=E:?:E
;:2@5E=EC.@E?8E?DE32;252?2=E:?:E2C:?8
2C:?8

36. Q

37. 52?Q

38. C6BD22CC2
;6?:C32;252?2=E:?:E2C:?82C:?88B2 4
52?

39. 8B2 4
C. Unsur Bunyi dan Pemanfaatan Gelombang
Bunyi
,?CEBE?CEB 3E?H: 2?D2B2 =2:? C63282: 36B:ED
1. Tinggi Nada Bunyi
(252A@@3292C2?C636=E?H2?52D6=296?86D29E:329G23E?H:
5:D:3E=2? @=69 CE2DE 36?52 H2?8 36B86D2B *62:? 32?H2 ;E=29
86D2B2? H2?8 5:92C:=2? 52=2 C2DE C6=2?8 G2DE D6BD6?DE 3E?H: H2?8
5:92C:=2? 22? C62:? ?H2B:?8
(2528232B#/$#3C6@B2?82?2D6B=:92DC652?86?6A6=2?
32D2?8 =:5: 5: ;2B:;2B: B@52 C6A652 H2?8 C652?8 36BAED2B :2 B@52 D6BC63ED
5:AED2BC62:?46A2D2A2293E?H:H2?85:92C:=2?22?C62:??H2B:?8
+6B?H2D2 A252 AED2B2? H2?8 =232D 3E?H: H2?8 D6B56?82B 36B?252
B6?529 (252 C22D AED2B2? B@52 C6A652 5:A6B46A2D 3E?H: H2?8 D6B56?82B
36B?252D:?88: 2=D6BC63ED63ED:2?329G2D:?88:?25236B82?DE?8
A252 7B6E6?C: CE36B 3E?H:
2. Kuat Bunyi
#E2D 3E?H: H2?8 5:92C:=2? 36B82?DE?8 A252 2A=:DE5@ 86D2B2?
(6B92D:2? #/$#3

40. H2?8 6?6B2?82? A6B4@322? A252 C6?2B 8:D2B
(6D:=29 C2=29 C2DE C6?2B 8:D2B 56?82? C:A2?82? H2?8 D:52 D6B=2=E
36C2B 6?82B2? 32:32: E2D 3E?H: H2?8 5:92C:=2? =2=E 32?5:?82?
56?82?E2D3E?H:H2?85:92C:=2?@=69C6?2BH2?8C22?2E?56?82?
C:A2?82? H2?8 =63:9 36C2B 52B:A252 C6E=2 (6D:2? 2?229 H2?8
6?892C:=2? 3E?H: =63:9 E2D
3. Warna Bunyi
-2B?2 3E?H: 6BEA22? 3E?H: 92C H2?8 5:D:3E=2? @=69 CE2DE
CE36B 3E?H: E?H: 8:D2B 36B3652 56?82? 3E?H: 3:@=2 :DE 2B6?2 252
G2B?2 3E?H: (6B36522? D6BC63ED D6B;25: 2B6?2 823E?82? ?252 2D2C 52?
?25252C2B52B:CE36B3E?H:36B36523652G2=2EAE?7B6E6?C:?H2C22
Gambar 3.3
Lidi dipegang oleh seorang anak
dan ditempelkan pada jeruji
roda yang berputar.
Gambar 3.4
Percobaan kuat bunyi yang
dihasilkan oleh getaran senar gitar
dengan (a) simpangan yang kecil
dan (b) simpangan yang besar.

41. 4. Batas Pendengaran
?52 D6?DE D6=29 6?86D29E: 329G2 2?EC:2 52? 96G2? 5:=6?82A:
56?82? 2=2D A6?56?82B2? H2?8 C6AEB?2 2E? 62AE2?
A6?56?82B2??H2 36B36523652 2D2C 62AE2? A6?56?82B2? 5:EEB
36B52C2B2? 7B6E6?C: 3E?H:
%2?EC:2 ?@B2=6:=:: 32D2C A6?56?82B2? 2?D2B2

42. 96BDI C2A2:
56?82?

43. 96BDI 26B29 7B6E6?C: D6BC63ED 5:?222? #! #
C652?82? 526B29 7B6E6?C: 5: 32G29

44. 96BDI 5:C63ED !
52? 526B29 5: 2D2C 7B6E6?C: 56?82B 2D2E 5: 2D2C

45. 96BDI 5:C63ED
# !
636B2A296G2?2AE6?56?82B3E?H:E=DB2C@?:3292?96G2?
C6A6BD: 6=6=2G2B H2?8 6:=:: 2=2D A6?8=:92D2? D:52 C632: 2=2D
A6?56?82B2??H2 6?88E?22? 3E?H: E=DB2C@?: E?DE 6?86D29E:
36?52 H2?8 252 5: 56A2??H2
5. Pemanfaatan Gelombang Bunyi
6=@32?8 3E?H: 32?H2 5:2?722D2? 52=2 69:5EA2? C692B:92B:
:C2=?H2E?DE6?6?DE2?652=22?=2ED6?42B:CE36B:?H252?
6?56D6C: 6BEC22? =@82 ,?DE 6?6?DE2? 652=22? =2ED 2=2D
A6?56D6C: H2?8 5:8E?22? 5:C63ED ! !# $ *@?2B
366B;2 56?82? 62?42B2? 86=@32?8 6E5:2? A2?DE=2? 86=@32?8
D6BC63ED 22? 5:D6B:2 @=69 $ 6?82? 6?86D29E: 646A2D2?
86=@32?8H2?85:EEB52?G2DED6AE986=@32?8D6BC63ED#652=22?
=2ED 52A2D 5:D6?DE2? 56?82? 6?88E?22? A6BC222? 36B:ED
pemancar penerima
gelombang
ultrasonik
Gambar 3.5
Sonar dapat digunakan untuk
mendeteksi kedalaman laut.
2 3
Sumber: www.mediajakartaselatan.com
1
54 Mudah dan Aktif Belajar Fisika untuk Kelas XII

46. ! $
N
2D@B C6D6?829 5: 56A2? A252 '34#/##0 9

47. 6?H2D22? C6D6?829
G2DE D6AE9 52B: C@?2B 6 D6A2D A62?DE=2?
B6E6?C: H2?8 5:8E?22? @=69 C@?2B 36B252 A252 526B29 E=DB2C@?:
H2:DE 5: 2D2C

48. 96BDI B6E6?C: D6BC63ED D:52 52A2D 5:56?82B 52?
A2?;2?8 86=@32?8 A252 526B29 E=DB2C@?: C2?82D 64:= C69:?882 5:7B2C:
H2?8 D6B;25: ;E82 C62:? 64:= 52? 86=@32?8 D:52 22? 6?H632B
#64:=?H2 A2?;2?8 86=@32?8 H2?8 5:8E?22? 52A2D ;E82 5:8E?22?
E?DE 6?56D6C: 36?5236?52 H2?8 64:= (6?88E?22? 86=@32?8
E=DB2C@?: D6B52A2D ;E82 A252 2=2D # ! ,* =2D D6BC63ED
EE?H2 5:8E?22? E?DE 6?82?2=:C:C 692:=2? 2D2E 6?56D6C:
@B82?@B82? 52=2 DE3E9
Gambar 3.6
Teknologi 3D USG terbaru sekarang
dapat melihat organ-organ tubuh
bayi dalam kandungan.
Contoh 3.3
*63E292=2DC@?2B5:8E?22?E?DE6?8EEB652=22?=2ED*6=2?8G2DEH2?8
5:42D2D@=69C@?2BE?DE86=@32?8A6B232D2?C2A2:632=:=28:6C@?2B252=29
C6@?:246A2DB232D86=@32?85:52=22:B=2ED252=29
CD6?DE2?=29
652=22?=2EDD6BC63ED
#7#$
:6D29E:$
CC
!$

49. CQ

50. QC
6D6B
25:=2EDD6BC63ED6:=::652=22?
6D6B
Kata Kunci
• tinggi nada
• kuat bunyi
• audiosonik
• infrasonik
• ultrasonik
• resonansi
• sonar
• ultrasonografi
4
5

51. Gelombang Bunyi 55
Tes Kompetensi Subbab C
'3,#-#0.#*#.#/$6-6.#5+*#0
?52 6?56?82B 92=:=:?D2B

52. C6@? C6D6=29 :=2D
D6B=:92D:246A2DB232D3E?H:5:E52B2
C
D6?DE2?;2B22C2=:=2DD6BC63ED52B:D6A2D?52

53. *63E29 2=2D C@?2B 5:8E?22? E?DE 6?8EEB
652=22?=2ED*6=2?8G2DEH2?85:42D2D@=69C@?2B
E?DE86=@32?86B232DC2A2:632=:6C@?2B
252=29C6@?:2652=22?=2ED

54. D6?DE2?
46A2DB232D3E?H:5:52=22:B=2ED
%6?82A26=6=2G2BH2?8D6B32?8A2522=292B:D:52
A6B?296?23B236?5236?52H2?82525:562D?H2
:2D:?88:?2525:?2:2?3282:2?229A6BE3292?
H2?8D6B;25:A252
2 7B6E6?C:
3 A2?;2?886=@32?8
4 46A2DB232D86=@32?8
5 2A=:DE5@86=@32?8
:2E2D3E?H:5:?2:2?3282:2?229A6BE3292?
H2?8D6B;25:A252
2 7B6E6?C:
3 A2?;2?886=@32?8
4 46A2DB232D86=@32?8
5 2A=:DE5@86=@32?8
D. Sifat-Sifat Gelombang Bunyi
?52 D6=29 6A6=2;2B: C:72DC:72D EE D6?D2?8 86=@32?8 H2:DE
A63:2C2? B67B2C: A62?DE=2? B67=6C: A6=6?DEB2? 5:7B2C:
:?D6B76B6?C:52?A@=2B:C2C:E?H:6BEA22?C2=29C2DE36?DE86=@32?8
'=69 2B6?2 :DE 86=@32?8 3E?H: ;E82 6?82=2: A6B:CD:G2A6B:CD:G2
D6BC63ED
1. Pemantulan Gelombang Bunyi
%6?82A2 C22D?52 36BD6B:2 5: C6:D2B D63:?8 C6=2=E 252 3E?H: H2?8
6?:BE2? CE2B2 ?52 D6BC63ED %6?82A2 CE2B2 ?52 D6B56?82B =63:9
6B2C 6D:2 36B252 5: 52=2 865E?8 #65E2 A6B:CD:G2 D6BC63ED
6?E?;E2?329G23E?H:52A2D5:A2?DE=2?,?DE6292:D6?D2?8
A62?DE=2? 3E?H: =2E2?=29 2D:F:D2C 36B:ED
Tugas Anda 3.3
Gelombang bunyi merupakan
gelombang longitudinal sehingga
tidak dapat mengalami dispersi dan
polarisasi. Diskusikanlah bersama
teman Anda, mengapa hal tersebut
bisa terjadi? Berikanlah penjelasan
ilmiah mengenai hal tersebut.
Aktivitas Fisika 3.2
Pemantulan Bunyi
Tujuan percobaan
Membuktikan peristiwa pemantulan bunyi.
Alat-Alat Percobaan
1. Weker 4. Dua buah pipa berdiameter 1 inci
2. Papan pemantul 5. Busur derajat
3. Meja 6. Kertas karton putih
Langkah-Langkah Percobaan
1. Susunlah alat seperti tampak pada gambar.
2. Letakkan jam weker di salah satu ujung pipa paralon.
3. Atur pipa paralon yang lain agar Anda dapat mendengar bunyi jam weker yang
paling jelas.
4. Gambarlah susunan pipa tersebut pada kertas karton putih yang Anda
letakkan di bawahnya. Ukurlah besar sudut datang dan sudut pantulnya.
5. Ulangi langkah percobaan ke-3 dan ke-4 dengan sudut yang berbeda.

55. Gambar 3.7
i r
Proses pemantulan bunyi.
2
3
Gambar 3.8
(a) Pada siang hari, arah rambat
bunyi melengkung ke atas.
(b) Pada malam hari, arah rambat
bunyi melengkung ke bawah.
$E:C2? 82B:C H2?8 ?52 3E2D D6?D2?8 CE5ED 52D2?8 CE5ED A2?DE=
52? 82B:C ?@B2= A252 A62?DE=2? 3E?H: 22? C22 56?82? #/$#3
(252 8232B D6BC63ED D6B=:92D 329G2 CE5ED 52D2?8 CE5ED A2?DE=
52? 82B:C ?@B2= D6B=6D2 A252 C2DE 3:52?8 52D2B 52?
%6?82A2 3E?H: 52=2 BE2?82? D6BDEDEA D6B56?82B =63:9 6B2C $6D2
5:?5:?8 BE2?82? H2?8 D6B=2=E 562D 6?H63232? 3E?H: A2?DE= D:52 4EEA
G2DE E?DE 6B232D C69:?882 3E?H: 52D2?8 52? 3E?H: A2?DE= D6B56?82B
C642B2 36BC222? 2= D6BC63ED 63ED:2? 329G2 3E?H: A2?DE= 52A2D
6A6BE2D3E?H:2C=:?H2!DE=29C6323?H2CE2B2EC:22?D6B56?82B=63:9
6B2C5:52=2BE2?82?52B:A2525:=2A2?82?D6B3E26B365256?82?862
H2?8 D6B;25: ;:2 ?52 36BD6B:2 5: 526B29 36BD63:?8 2B2 D63:?8 52?
CE36B 3E?H: H2?8 4EEA ;2E9 6?H63232? 3E?H: A2?DE= 66B=E2?
G2DEH2?84EEA=22E?DE6B232DC2A2:A6?56?82B2?:32D?H2
3E?H: A2?DE= 22? D6B56?82B C6D6=29 3E?H: 2C=: 636B2A2 A6B:CD:G2 D6BC63ED
6BEA22? A6?82=22? H2?8 C6B:?8 ?52 D6E2?
Ingatlah
56 Mudah dan Aktif Belajar Fisika untuk Kelas XII
2. Pembiasan Gelombang Bunyi
?52 D6=29 6?86D29E: 86=@32?8 3E?H:
6B232D 6 C6E2 2B29 52? 86=@32?8 3E?H: D:52
52A2D D6BA@=2B:C2C: %6?82A2 A252 2=2 92B: CE2B2
25I2? 2D2E CE2B2 D6B:22? H2?8 4EEA ;2E9 D6B56?82B
=63:9 ;6=2C 52B:A252 C:2?8 92B: (252 C:2?8 92B: CE9E
E52B2 5: A6BE22? =63:9 D:?88: 52B:A252 5: 2D2C?H2
2= D6BC63ED 6?H63232? =2A:C2? E52B2 A252 328:2?
2D2C=63:9B2A2D52B:A2525:32G29?H2*632=:?H2A252
2=2 92B: =2A:C2? E52B2 5: A6BE22? =63:9 B2A2D
52B:A252 5: 2D2C?H2 :32D?H2 A252 C:2?8 92B: ;:2
CE36B 3E?H: 52D2?8 C642B2 9@B:I@?D2= D6B9252A
A6?56?82B52A2D5:A2CD:2?2B29B232D3E?H:22?6=6?8E?862D2C
C652?82? A252 2=2 92B: 2B29 B232D 3E?H: 22? 6=6?8E?8 6
32G29 (6B92D:2? #/$#3
A2 H2?8 22? D6B;25: ;:2 3E?H: 52D2?8?H2 6B232D F6BD:2= 6
32G29 (252 2=2 92B: 2B29 B232D 3E?H: 5:3:2C2? 6?562D: 82B:C
?@B2=*632=:?H2A252C:2?892B:2B29B232D3E?H:5:3:2C2?6?;2E9:
82B:C ?@B2=
*6CE2: 56?82? 9EE A63:2C2? 86=@32?8 329G2 86=@32?8
52D2?8 52B: 65:E EB2?8 B2A2D 6 65:E =63:9 B2A2D 22? 5:3:2C2?
6?562D: 82B:C ?@B2= 2D2E C632=:?H2
3. Difraksi Gelombang Bunyi
A229 86=@32?8 3E?H: 52A2D 6?82=2: 5:7B2C: 2D2E A6=6?DEB2?
(6B:CD:G2 A6=6?DEB2? 3E?H: 52A2D 5:22D: 6D:2 ?52 6?56?82B 56BE
3E?H:@3:=6=:?D2C:526B29A6B3E:D2?H2?836B6=@CE2B2A6B422A2?
D62?D62? ?52 5: BE2?82? H2?8 36B3652 2D2E 242 A632D2C =@6D
A632H2B2? 5: C63E29 32? H2?8 C6?82;2 5:3E2D 56?82? 3636B2A2 =E32?8
64:=282B86=@32?83E?H:D:5262?DE=G2=2EAE?2B29B232D3E?H:
D:52 36BEA2 82B:C =EBEC +:82 A6B:CD:G2 D6BC63ED 6BEA22? 4@?D@9
A6?6B2A2? 5:7B2C: 3E?H: 25: 2A229 H2?8 5:2CE5 56?82? 5:7B2C:
:DE :7B2C: 252=29 A6B:CD:G2 A6=6?DEB2? 86=@32?8 6D:2 6=6G2D:
46=29 H2?8 EEB2? 46=29?H2 C6@B56 56?82? A2?;2?8 86=@32?8?H2
A N C
Pelayangan bunyi terjadi karena
adanya interferensi dua gelombang
yang frekuensinya berbeda sedikit.

56. Gelombang Bunyi 57
$2=E 6?82A2 86=@32?8 3E?H: E529 6?82=2: 5:7B2C:
6=@32?8 3E?H: 5: E52B2 6:=:: A2?;2?8 86=@32?8 C6:D2B 3636B2A2
C6?D:6D6B C2A2: 3636B2A2 6D6B 2?5:?82? 56?82? 4292H2 H2?8
6:=::A2?;2?886=@32?836B:C2B
!DE=29C6323?H286=@32?8
3E?H: =63:9 E529 E?DE D6B5:7B2C:
4. Interferensi Gelombang Bunyi
#6D:2 ?52 36B5:B: 5: 56A2? 5E2 #! A6?86B2C CE2B2 C63282:
CE36B3E?H:6E5:2?36B;2=2?=EBECC6;2;2B56?82?82B:CA6?89E3E?865E2
#! D6BC63ED+2=22C6D6=29:DE?5222?6?56?82B3E?H:=629
52?C6C22D6E5:2?D6B56?82B3E?H:E2DE?H:E2DD6B;25:6D:2CEA6BA@C:C:
52B: 5E2 86=@32?8 3E?H: 6?892C:=2? :?D6B76B6?C: 56CDBED:7 !?D6B76B6?C:
D6BC63ED D6B;25: ;:2 3652 =:?D2C2??H2 6BEA22? 6=:A2D2? 3:=2?82? 3E=2D 52B:
C6D6?829A2?;2?886=@32?83E?H:C642B22D62D:C5:DE=:C2?C63282:36B:ED
!

57. 56?82?

58. 52?

59. 36BDEBEDDEBEDE?DE3E?H:E2DA6BD223E?H:
E2D 65E2 52? 3E?H: E2D 6D:82
5. Pelayangan Bunyi
!?D6B76B6?C: H2?8 5:D:3E=2? 52B: 5E2 86=@32?8 3E?H: 52A2D
6?H63232?A6B:CD:G2A6=2H2?82?3E?H:H2:DEA6?8E2D2?52?A6=6292?
3E?H: 2=D6BC63EDD6B;25:2:32DCEA6BA@C:C:5E286=@32?8H2?86:=::
7B6E6?C: H2?8 C65::D 36B3652 52? 6B232D 52=2 2B29 H2?8 C22
25: C2DE A6=2H2?82? 5:567:?:C:2? C63282: 5E2 3E?H: 6B2C 2D2E 5E2
3E?H: =629 H2?8 D6B;25: C642B2 36BEBED2? =2H2?82? E2D N =629 N
E2D 2D2E =629 N E2D N =629
:2 65E2 86=@32?8 3E?H: D6BC63ED 6B232D 36BC222? 22?
6?892C:=2? 3E?H: A2=:?8 E2D C22D 72C6 65E2?H2 C22 :2 65E2
86D2B2? 36B=2G2?2? 72C6 22? 5:92C:=2? 3E?H: A2=:?8 =629
%:C2=2? 5E2 CE36B 3E?H: 6:=:: 7B6E6?C: 52?

60. C65::D
36B3652 C:A2?82? C6D:2A 86=@32?8 A252 A@C:C: D6BD6?DE 252=29
C:?

61. 52?

62. C:?

63. 6?82?56::2?CEA6BA@C:C:C:A2?82?65E286=@32?8D6BC63ED252=29

65. C:?

66. C:?

67. C:?

68. C:?

69. 56?82? 6?88E?22? 2DEB2? C:?EC 22? 5:A6B@=69

70. 4@C

71. C:?

75. 4@C

77. C:?

80. :2

81. 52?

82. 22
f 52?

87. (6BC222? CEA6BA@C:C: 52A2D 5:DE=:C2? 6?;25:

88. 4@C

89. C:?

90. AC:?

91. N
Kata Kunci
• dispersi
• refraksi
• refleksi
• difraksi
• interferensi
• polarisasi
• superposisi
sin A + sin B = 2 cos 1
2 (A–B) sin 1
2
(A+B)
Ingatlah

92. 6B52C2B2? '34#/##0 9 :?D6?C:D2C 3E?H: 22? 2C:2= ;:2

93. '=69 2B6?2 :DE =2H2?82? 3E?H: D6B;25: ;:2

94. 4@C

95. 36B?:=2: 52? N C69:?882 7B6E6?C: =2H2?82??H2 252=29
#6D6B2?82?
7B6E6?C: A6=2H2?82? I

96. 7B6E6?C: 86=@32?8

97. I
7B6E6?C: 86=@32?8 I
Contoh 3.4

98. 4@C

99. N

100. f f f p ( ) 1 2
N
E2ED2CC6?2BH2?8:56?D:636B:2??25252C2B56?82?7B6E6?C:

101. I:2
D682?82?C2=29C2DEC6?2B5:D232936B2A2A6=2H2?82?H2?8D6B;25:
#7#$
:6D29E:

102. I

103. 52A2D5:9:DE?856?82?A6BC222?

105. Pembahasan Soal
f F F
f F F
Tes Kompetensi Subbab D
'3,#-#0.#*#.#/$6-6.#5+*#0
6=2C2?A6?86BD:2?5:7B2C:86=@32?83E?H:

106. :2 252 D:82 CE36B 3E?H: H2?8 :56?D: 5:=6D22?
2C:?82C:?8 36B;2B2 56?82? H2?8 =2:??H2
2A2?29D6B;25::?D6B76B6?C:2C:E52B:6D:82
CE36B3E?H:D6BC63ED

107. E. Dawai dan Pipa Organa sebagai Sumber Bunyi
1. Frekuensi Gelombang pada Dawai
?52D6=296A6=2;2B:329G236?5236?52H2?836B86D2B6BEA22?
CE36B3E?H:D6D2A:D:52C6E23E?H:52A2D5:56?82B@=69D6=:?822?EC:2
2= D6BC63ED 5:C63232? D6=:?82 2?EC:2 ?@B2= 6:=:: 7B6E6?C:
232?8 :?:2= H2:DE 7B6E6?C: D6B6?529 52B: CE36B 3E?H: H2?8 2C:9
52A2D 5:D6B:2 @=69 D6=:?82
58 Mudah dan Aktif Belajar Fisika untuk Kelas XII
E23E29C6?2BH2?8:56?D:636B:2??25252C2B
56?82? 7B6E6?C:
I :2 D682?82? C2=29 C2DE
52G2:5:D232936B2A27B6E6?C:A6=2H2?82?H2?8
D6B;25:

108. Hz

109. I
B6E6?C:A6=2H2?82?5:A6B@=6956?82?6?88E?22?'34#/##09252=29
N

110. N

111. IN I
25:7B6E6?C:A6=2H2?82??H2252=29N I
Dua buah dawai baja yang identik
memberikan nada dasar dengan
frekuensi 400 Hz. Bila tegangan
dalam salah satu dawai ditambah
2%, frekuensi pelayangan yang
terjadi adalah ....
a. 0 Hz d. 6 Hz
b. 2 Hz e. 8 Hz
c. 4 Hz
Tes ITB 1975
Pembahasan:
Diketahui:
f0 = 400 Hz
Tegangan ditambah 2%
p’ = F + 2% F = 1,02 F
maka
0 1,02 ’
1,01
sehingga frekuensi layangannya
adalah
fp = (f2 – f1)
= (1,01 f0 – f0)
= 0,01 f0
= 0,01 · 400 Hz
= 4 Hz
Jawaban: c

112. *2=29 C2DE CE36B 3E?H: 252=29 52G2: 8:D2B 252 H2?8 5:92C:=2?
52G2: 8:D2B 52A2D 5:E329E329 56?82? 42B2 6?62? C6?2B A252 D:D:
D:D: D6BD6?DE (@=2 86=@32?8 H2?8 52A2D D6B;25: A252 52G2: 8:D2B
5:DE?;E2? A252 #/$#3 56?82? 36BE329E329
*2DE 52G2: 52A2D 636?DE 36B3282: 7B6E6?C: 2D2E A@=2 86D2B2?
1
2 2
2 3 4 5
Gambar 3.9
(a) Nada dasar f0;
(b) Nada atas pertama f1;
(c) Nada atas kedua f2;
(d) Nada atas ketiga f3.
Informasi
untuk Anda
Information for You
Gelombang Bunyi 59
(@=2 86D2B2? 52G2: A252 #/$#3 # 6?892C:=2? ?252 52C2B

113. 2D2E

114. 22
56?82?
$ $

115. (@=2 86D2B2? 52G2: A252 #/$#3 $ 6?892C:=2? ?252 2D2C
A6BD22 56?82? 2D2E 22

116. $ $
(@=286D2B2?52G2:A252#/$#3 %6?892C:=2??2522D2C65E2

117. 2D2E

118. 56?82?

120. $ $ $
22

124. (@=286D2B2?52G2:A252#/$#36?892C:=2??2522D2C6D:82
56?82?

125. 2D2E

126. $ $ $
22

128. (6B32?5:?82? 7B6E6?C: ?252?252 A252 52G2: H2?8 5:92C:=2?
36BEA2 A@=2 86=@32?8 C6A6BD: A252 #/$#3 252=29 C63282: 36B:ED

129. N
'=69 2B6?2 46A2D B232D 86=@32?8 A252 52G2: C6CE2: 56?82? 92C:=
2'3%1$##0 '.' H2:DE $
22 5:A6B@=69
2 7B6E6?C: ?252 52C2B

131. 3 7B6E6?C: ?252 2D2C A6BD22
4 7B6E6?C: ?252 2D2C 65E2

134. 5 7B6E6?C: ?252 2D2C 6

135. N
0
1
2
2
3
2
C6A6BD: D2A2 A252 #/$#3
Echolocation adalah bentuk sensor
yang digunakan oleh binatang
seperti kelelawar, paus, dan lumba-lumba.
Binatang tersebut
memancarkan gelombang suara
(gelombang longitudinal), kemudian
dipantulkan oleh objek. Gelombang
pantul kemudian dideteksi oleh
binatang tersebut. Gelombang
echolocation yang dipancarkan oleh
kelelawar memiliki frekuensi sekitar
175.000 Hz.
Echolocation is a form of sensory
perception used by animals such as
bats, toothed whales, and porpoises.
The animal emits a pulse of sound (a
longitudinal wave) which is reflected
from objects. The reflected pulse is
detected by the animal. Echolocation
wave emitted by bats have
frequencies of about 175.000 Hz.

136. (6BC222? 7B6E6?C: ?252?252 D6BC63ED 2=: A6BD22 5:E?82A2? @=69
'34'00' C69:?882 '34#/##0 9 D6BC63ED 5:6?2= 56?82? 6-6/
'34'00'
Contoh 3.5
2D2E

138. 2D2E

139. 2. Pipa Organa dan Pola Gelombangnya
+6=29 ?52 6D29E: 329G2 36?52 H2?8 36B86D2B 52A2D6?892C:=2?
3E?H: +:52 92?H2 36?52 A252D C6A6BD: 52G2: D2=: 2EAE? A6=2D =@82
H2?8 52A2D 36B86D2B 86D2B2? AE? 52A2D D6B;25: A252 82C :C2=?H2 E52B2
6D2B2? @=@ E52B2 A252 C6BE=:?8 22? 6?892C:=2? 3E?H: +:?88:
?252 H2?8 5:A6B@=69 52B: C63E29 C6BE=:?8 52A2D 5:2DEB 7B6E6?C:?H2 :
2?D2B2 A6B2?82D EC: C656B92?2 H2?8 52A2D 6?892C:=2? 86D2B2?
@=@ E52B2 C6=2:? C6BE=:?8 252=29 A:A2 @B82?2 +6B52A2D 5E2 242
A:A2 @B82?2 H2:DE A:A2 @B82?2 D6B3E2 52? A:A2 @B82?2 D6BDEDEA
a. Pipa Organa Terbuka
(:A2@B82?2D6B3E2252=292=2DD:EA36BEA2D23E?8H2?865E2E;E?8
A6?2A2?8?H2 D6B3E2 #65E2 E;E?8 A:A2 @B82?2 D6B3E2 6?;25: A6BED
86=@32?8 A252 @=@ E52B2 (@=2 86=@32?8 H2?8 5:92C:=2? C6A6BD:
D2A2 A252 #/$#3 B6E6?C: H2?8 5:92C:=2? @=69 A:A2 @B82?2
D6B3E2 252=29 C63282: 36B:ED
252 52C2B
60 Mudah dan Aktif Belajar Fisika untuk Kelas XII

140. 2D2E

141. B6E6?C: H2?8 5:92C:=2?
$ $

142. Gambar 3.10
Seruling merupakan pipa
organa terbuka.
*6ED2C52G2:H2?865E2E;E?8?H2D6B:2D6:=::A2?;2?8

143. 2CC2;6?:C?H2
8 4
6?892C:=2?7B6E6?C:?25252C2B
I
2 :DE?8=2982H2D682?82?52G2:
3 6B2A22936C2B7B6E6?C:52?A2?;2?886=@32?8A252?2522D2CA6BD22
4 +6?DE2?=29 7B6E6?C: 52? A2?;2?8 86=@32?8 A252 52G2: E?DE ?252 2D2C
65E2
#7#$
:6D29E:

144. 8 4
I
2 6?82?6?88E?22?'34#/##09E?DE?25252C2B5:A6B@=69

146. Q
N
8 4

147. I

148. 25:36C2B82H2D682?82?52G2:252=29

149. 3 B6E6?C:?2522D2CA6BD22252=29
2D2E

150. I

151. I
(2?;2?886=@32?8A252?2522D2CA6BD22252=29

152. 4 B6E6?C:A252?2522D2C65E2

153. 252=29
2D2E

154. I
I
(2?;2?886=@32?8A252?2522D2C65E2252=29

157. nada dasar atau
harmonik pertama
1
2
0
nada atas pertama atau
harmonik kedua
1
nada atas ketiga atau
harmonik ketiga
3
2
Gambar 3.11
Pola gelombang resonansi
suatu pipa organa terbuka.
Gelombang Bunyi 61

158. 252 2D2C A6BD22 2D2E
B6E6?C: H2?8 5:92C:=2?
$ $

159. 2D2E

160. 252 2D2C 65E2

162. B6E6?C: H2?8 5:92C:=2?
$ $

165. 252 2D2C 6 ?

167. B6E6?C: H2?8 5:92C:=2?

168. $
N
(6B32?5:?82? 7B6E6?C: 86=@32?8 H2?8 5::=:: @=@ E52B2 A252
A:A2 @B82?2 D6B3E2 C22 56?82? A6B32?5:?82? 7B6E6?C: 86=@32?8
A252 52G2: (6B32?5:?82? 7B6E6?C: H2?8 5:92C:=2? @=69 C6D:2A A@=2
86=@32?8 E?DE A:A2 @B82?2 D6B3E2 252=29

169. $ $ $

171. N
'34#/##0 9 H2?8 6BEA22? A6B32?5:?82? 7B6E6?C: 5:6?2=
C63282: 6-6/ '3016..+ 52? 6BEA22? A6B32?5:?82? 3:=2?82?
3:=2?82? 3E=2D
Contoh 3.6
*63E29A:A2@B82?2D6B3E2A2?;2?8?H2
4+6?DE2?
?25252C2BH2?85:92C:=2?A:A2D6BC63ED;:246A2DB232D
3E?H:5:E52B2
C
#7#$
:6D29E:A2?;2?8A:A2
4
46A2DB232D3E?H:$
C
6?82?6?88E?22?'34#/##097B6E6?C:?25252C2B5:A6B@=69

172. 2D2E

173. 22

174. 1
40cm
2
*H2B2DD6B;25:?H2?25252C2BH2:DE
C

175. I
$
Contoh 3.7
*63E29A:A2@B82?2D6B3E2H2?8A2?;2?8?H252?7B6E6?C:92B@?:?H2
36BDEBEDDEBED

176. I52?
I+6?DE2?46A2DB232D3E?H:A252A:A2@B82?2
D6BC63ED

177. $
$
$
b. Pipa Organa Tertutup
(:A2 @B82?2 D6BDEDEA 252=29 2=2D D:EA 36BEA2 D23E?8 H2?8 C2=29 C2DE
E;E?8 A6?2A2?8?H2 D6BDEDEA *2=29 C2DE E;E?8 A:A2 @B82?2 D6BDEDEA
6?;25: C:AE= 86=@32?8 A252 @=@ E52B2 52? E;E?8 =2:??H2 H2?8
D6B3E26?;25:A6BED86=@32?8(@=286=@32?8H2?85:92C:=2?D2A2
C6A6BD:#/$#3
B6E6?C:H2?85:92C:=2?@=69A:A2@B82?2D6BDEDEA
252=29 C63282: 36B:ED
252 52C2B
$ $ $
harmonik pertama
1
4
harmonik kedua
3
4
0
1
harmonik ketiga
5
4
2
62 Mudah dan Aktif Belajar Fisika untuk Kelas XII
2D2E
7B6E6?C: H2?8 5:92C:=2?
$ $
2D2E

178. 252 2D2C A6BD22
7B6E6?C: H2?8 5:92C:=2?
$ $
252 2D2C 65E2

179. 2D2E

180. 7B6E6?C: H2?8 5:92C:=2?

181. $ $

182. 252 2D2C 6N ?
2D2E

183. B6E6?C: H2?8 5:92C:=2?

184. $
N
(6B32?5:?82? 7B6E6?C: H2?8 5:92C:=2? @=69 C6D:2A A@=2 86=@32?8
E?DE A:A2 @B82?2 D6BDEDEA 252=29

185. N

186. '34#/##0 9
H2?8 6BEA22? A6B32?5:?82? 7B6E6?C: 5:6?2=
C63282: 6-6/ '3016..+ 52? 6BEA22? A6B32?5:?82? 3:=2?82?
3:=2?82? 82?;:=
Gambar 3.12
Pola gelombang resonansi pada
suatu pipa organa tertutup.
#7#$
%:C2=2??

187. I52??
I
6?82?6?88E?22?'34#/##095:A6B@=69
?N?J

188. NK

189. I

190. I

191. $
C

192. Pembahasan Soal
f v v
f v v
v
A A
B
Gelombang Bunyi 63
Contoh 3.8
*63E29A:A2@B82?2D6BDEDEA6:=::A2?;2?8

193. 4A23:=246A2DB232D3E?H:
C22D:DE
CD6?DE2?7B6E6?C:?25252C2B?2522D2CA6BD2252??2522D2C
65E2

194. #7#$
:6D29E:

195. 4

196. $
C
$
6B52C2B2?'34#/##09

197. 5:A6B@=69
$
M ?25252C2B
C
I

198. M ?2522D2CA6BD22
0

199. 1

200. I
M ?2522D2C65E2

201. 0

202. 1
I
Contoh 3.9
*63E29A:A2@B82?2D6B3E256?82?A2?;2?8
4D6B;25:
3E29C:AE=252
A:A2@B82?2D6BC63ED36B6C@?2?C:56?82?A:A2@B82?2D6BDEDEA

203. 52?636?DE

204. 3E29C:AE=6B2A2A2?;2?8A:A2@B82?2H2?8D6BDEDEA
#7#$
)6C@?2?C:D6B;25:;:2C2256?82?

205. (2?;2?8 A:A2 @B82?2 D6B3E2
4 D6B;25:
C:AE= 52?
A6BED

206. C69:?882

208. 2D2E
22

209. 4
4
(252A:A2@B82?2D6BDEDEAD6B;25:

210. C:AE=52?

211. A6BED
C69:?882

213. 2D2E
22

216. $

217. 56?82?6?88E?22?CH2B2DB6C@?2?C:A2?;2?8A:A2@B82?2D6BDEDEA

218. 52A2D5:9:DE?8

223. 4
4
$ $
Pipa organa terbuka A dan pipa
organa tertutup sebelah B memiliki
panjang yang sama. Perbandingan
frekuensi nada atas pertama antara
pipa organa A dengan pipa organa B
adalah ....
a. 1 : 1 d. 3 : 2
b. 2 : 1 e. 4 : 3
c. 2 : 3
UMPTN 1995
Pembahasan:
Pipa organa terbuka:
1 , , 3 , ....
A 2 2
Pada nada atas pertama:
A A
A
x
Pipa organa tertutup:
1 , 3 , 5 , ....
B 4 4 4
Pada nada atas pertama:
3 4
B 4 3 B
3
4 4
3
B
B
B
Untuk A B , diperoleh
4
3 3
4
B
v
f
f v
Jawaban: e
3. Resonansi
(6B:CD:G2 :ED 36B86D2B?H2 CE2DE 36?52 2B6?2 252 36?52 =2:? H2?8
36B86D2B5:C63ED !!*H2B2DD6B;25:?H2B6C@?2?C:252=297B6E6?C:86D2B
65E2 36?52 92BEC C22 2D2E 7B6E6?C: 36?52 H2?8 :ED 36B86D2B C22
56?82? 6=:A2D2? 3:=2?82? 3E=2D 52B: 7B6E6?C: 36?52 H2?8 36B86D2B
(6B92D:2? 5E2 4@?D@9 A6B:CD:G2 B6C@?2?C: 36B:ED :?:
a. Resonansi pada Garputala
:2 C63E29 82BAED2=2 5:AEE= 82BAED2=2 D6BC63ED 36B86D2B C6A6BD:
A252 #/$#3 B6E6?C: 86=@32?8 3E?H: H2?8 5:92C:=2?
36B82?DE?8 A252 36?DE 36C2B 52? 3292? =@82 82BAED2=2 D6BC63ED
#6D:2 5:562D2? A252 82BAED2=2 H2?8 =2:? 52? 6:=:: 7B6E6?C: 3E?H:
C22 82BAED2=2 65E2 22? :ED 36B86D2B (6B:CD:G2 :ED 36B86D2B?H2
82BAED2=2 H2?8 65E2 5:C63ED B6C@?2?C:
Gambar 3.13
Dua garputala yang memiliki
frekuensi yang sama akan
beresonansi.

224. b. Resonansi pada Kolom Udara
(6B92D:2? #/$#3

225. H2?8 6A6B=:92D2? A6B:CD:G2 B6C@?2?C:
A252 @=@ E52B2 :2 @=@ E52B2 H2?8 D6B=6D2 5: 2D2C A6BE22? 2:B
5:86D2B2? 56?82? 6?88E?22? C63E29 82BAED2=2 @=6E=@=6E=
E52B25:52=2@=@E52B222?:ED36B86D2B*H2B2DD6B;25:?H2B6C@?2?C:
A252 @=@ E52B2 252=29
D6A2DA252A6BE22?2:B92BECD6B36?DEB2A2D2? C:AE=86=@32?8

226. A252 E;E?8 A6BE22? @=@ E52B2 6BEA22? A6BED B6?882?82?
86=@32?8
,?DE6?52A2D2?B6C@?2?C:A2?;2?8@=@E52B25:2D2CA6BE22?
92BEC5:E329E32952AE?7B6E6?C:52?A2?;2?886=@32?83E?H:?H2D6D2A
)6C@?2?C:A6BD2222?D6B;25:;:2A2?;2?8@=@E52B25:2D2CA6BE22?
A2?;2?8 @=@ E52B2 6N
A2?;2?8 86=@32?8 3E?H:
:2 7B6E6?C: 82BAED2=2 5:6D29E: 46A2D B232D 86=@32?8 3E?H: 82BAED2=2
52A2D 5:D6?DE2? 6=2=E: A6BC222? $ 82B ?52 52A2D
6?82A=:2C:2?AB@C6CA6?8EEB2?46A2DB232D3E?H:5:E52B236B52C2B2?
@?C6A B6C@?2?C: 3E?H: A252 @=@ E52B2 =2E2?=29 2D:F:D2C 36B:ED
64 Mudah dan Aktif Belajar Fisika untuk Kelas XII
N
Aktivitas Fisika 3.3
gelas
air
mineral
garputala
paralon
selang
plastik
neon
gabus
Cepat Rambat Bunyi
Tujuan Percobaan
Mengukur cepat rambat bunyi di udara.
Alat-Alat Percobaan
1. Garputala
2. Lampu neon yang sudah tidak terpakai
3. Botol air mineral 100 m
4. Selang plastik berdiameter 1,5 cm dan panjang 2 m
5. Pipa paralon berdiameter 3 cm dan panjang 1 m
6. Penjepit
7. Penggaris
8. Gabus sebagai sumbat
Langkah-Langkah Percobaan
1. Rangkailah alat-alat tersebut seperti pada gambar.
2. Isilah lampu neon dengan air sampai ketinggian
kolom udara 5 cm.
3. Getarkanlah garputala di atas lampu neon yang
terbuka.
4. Lakukan pemompaan terhadap air dari lampu neon
agar air keluar melalui selang dengan botol air mineral secara perlahan-lahan.
2:B
B6C@?2?C: 65E2
B6C@?2?C: 6D:82
52? C6D6BEC?H2
*22 92=?H2 56?82? 86D2B2? E52B2 A252 A:A2 @B82?2 D6BDEDEA
9E3E?82? A2?;2?8 @=@ E52B2 D6B9252A A2?;2?8 86=@32?8 3E?H:
A252 A6B:CD:G2 B6C@?2?C: @=2 E52B2 52A2D 5:DE=:C C63282: 36B:ED

227. #6D6B2?82?

228. Gambar 3.14
Sebuah kolom udara di atas
permukaan air digetarkan oleh
sebuah garputala.

229. Ingatlah
Gelombang Bunyi 65
Data Pengamatan Resonansi Udara untuk Percobaan Cepat Rambat Udara
Resonansi ke–n Panjang Kolom Udara ( )
1.
2.
3.
....
....
....
6B52C2B2? 2D:F:D2C D6BC63ED ?52 22? 6?52A2D2? 52D2
A2?;2?8 @=@ E52B2 #6E5:2? 3282:2?229 42B2 6?89:DE?8 46A2D
B232D 3E?H: 5: E52B2 (6B92D:2? 632=: '34#/##0 9

230. ?
:2 ?52 6?89:DE?8 C6=:C:9 1
52? 0
22? 5:52A2D2?
N
N

231. N
'=692B6?2A2?;2?886=@32?8CE5295:6D29E:?5252A2D6?89:DE?8
46A2D B232D?H2 36B52C2B2? A6BC222?
$
N
#6D6B2?82?
$ 46A2D B232D 3E?H: C
A2?;2?8 86=@32?8 82BAED2=2
7B6E6?C: 82BAED2=2 I
Nilai frekuensi setiap garputala
sudah diketahui. Analoginya
seperti nilai fokus dari lensa.
5. Berhentilah memompa air pada saat terdengar bunyi mendengung. Ukur
panjang kolom saat itu dan catat sebagai l1 (resonansi pertama) pada tabel
pengamatan seperti berikut.
6. Turunkan permukaan air dalam lampu neon sampai terdengar bunyi
mendengung lagi. Ukur panjang kolom saat itu dan catat sebagai l2
(resonansi kedua) pada tabel pengamatan.
7. Ulangi langkah tersebut sampai didapatkan l3, l4, dan seterusnya.
Contoh 3.10
(2528232BD2A2C63E29@=@E52B2H2?8A2?;2?8?H2 E?DE
6?892C:=2?B6C@?2?C:@=@E52B2C642B2F6BD:2=:2@=@E52B2
D6BA6?566?892C:=2? B6C@?2?C: C22D

232. 4 D6?DE2?
7B6E6?C:82BAED2=2
+6?DE2?AE=2A2?;2?8@=@E52B2A252B6C@?2?C:C6=2?;ED?H2
:6D29E:46A2DB232D3E?H:5:E52B2$
C
#7#$
:6D29E:

233. 4

234. $
C
(252A6B:CD:G2B6C@?2?C:A6BD2252=2@=@E52B236B=2E9E3E?82?36B:ED
2D2E

235. 4 4

236. 52?E?DEB6C@?2?C:65E2
F. Energi Gelombang Bunyi
+6=29?526D29E:329G286=@32?8252=2986D2B2?H2?86B232D
6=2=E: I2D A6B2?D2B2 65:E D6D2A: 65:E?H2 D:52 :ED 6B232D
2=2A6B232D2??H286=@32?86:?5292?6?6B8:52B:C2DED6A2D
6 D6A2D =2:? ?6B8: 86=@32?8 3E?H: H2?8 5:D:3E=2? 52B: CE2B2
A6C2G2D ;6D !# ! 52A2D 664292? 242 ;6?56=2 CE2DE 32?8E?2?
2= D6BC63ED 6?E?;E2? 329G2 6?6B8: 86=@32?8 3E?H: 6=2E2?
A6B232D2? ?6B8: 86=@32?8 3E?H: 52A2D 5:D6?DE2? 52B: 6?6B8:
A@D6?C:2= 2C:E 86D2B2? 2B6?2 3E?H: 6BEA22? 86=@32?8 =@?8:
DE5:?2= 92C:= A6B232D2? 86D2B2? '=69 2B6?2 :DE 6?6B8: 86=@32?8
3E?H: 52A2D 5:?H2D22? 56?82? H2:DE C63282: 36B:ED
66 Mudah dan Aktif Belajar Fisika untuk Kelas XII

238. 2B6?2

239. Tes Kompetensi Subbab E
'3,#-#0.#*#.#/$6-6.#5+*#0
(252C6ED2C52G2:H2?8A2?;2?8?H2

240. 56?82?2CC2

241. 8A6B232D2?86=@32?8DB2?F6BC2=H2?85:92C:=2?
6:=::646A2D2?
C+6?DE2?D682?82?52G2:
D6BC63ED

242. +2=:H2?8A2?;2?8?H25:D682?82?56?82?82H2

243. (6B232D2?86=@32?8DB2?CF6BC2=H2?85:92C:=2?
6:=:: 646A2D2?
C +6?DE2? 2CC2 D2=:
D6BC63ED
E2ED2CD2=:H2?8C22A2?;2?85:D2B:@=6982H2H2?8
C22%2CC2D2=:A6BD222=:2CC2D2=:65E2+2=:
A6BD22 5:86D2B2? 56?82? 7B6E6?C:

244. I
C652?82?D2=:65E2
I:2A2?;2?886=@32?8
A252D2=:A6BD224D6?DE2?A2?;2?886=@32?8
A252D2=:65E2
*63E29 86=@32?8 C:?EC 6B232D A252 D2=: H2?8
A2?;2?8?H2
436B86B252B:C:A2?82?:?:E
6 2C:E *E2DE D:D: 66B=E2? G2DE
C6@?52=286B2D6BC63ED+6?DE2?
2 A6B:@5686=@32?8
3 7B6E6?C:86=@32?8
4 82H2D682?8D2=:;:25:6D29E:A2?;2?886=@32?8
52?2CC2D2=:

245. 8B2
*63E29 A:A2 @B82?2 D6B3E2 A2?;2?8?H2
4
+6?DE2?7B6E6?C:?25252C2BH2?85:92C:=2?A:A2
D6BC63ED;:246A2DB232D3E?H:5:E52B2
C
*63E29 A:A2 @B82?2 D6BDEDEA A2?;2?8?H2

246. 4
+6?DE2??25252C2BH2?85:92C:=2?A:A2:DE;:246A2D
B232D3E?H:5:E52B2
C
+6?DE2?A2?;2?8:?:EA:A2@B82?2D6B3E2H2?8
36B6C@?2?C:56?82?82BAED2=2H2?836B86D2B56?82?
7B6E6?C:
I;:246A2DB232D3E?H:5:E52B2
C
Kata Kunci
• resonansi
• Hukum Mersenne
• pipa organa
• Hukum I Bernoulli
• Hukum II Bernoulli
C
I
$
25:7B6E6?C:82BAED2=2252=29
I
(2?;2?8@=@E52B2A252B6C@?2?C:65E252?6D:82

247. 52A2D5:D6?DE2?
56?82?'34#/##09 H2:DE

248. 252=29

249. 25:E?DEB6C@?2?C:6D:82

250. m

252. P r1
r2
Gambar 3.15
Sumber bunyi berupa titik.
Semakin jauh dari sumber bunyi,
luas permukaan semakin besar.
Ingatlah
Gelombang Bunyi 67
2D2E

253. 22 5:A6B@=69

254. N

255. #6D6B2?82?
2CC2 A2BD:6= 8
2A=:DE5@ 86=@32?8
7B6E6?C: 86D2B I
@?CD2?D2 A682C
6B52C2B2?'34#/##09
6?6B8:H2?85:A:?5292?@=69CE2DE
86=@32?8 C632?5:?8 56?82? E25B2D 2A=:DE5@?H2
1. Intensitas Gelombang Bunyi
!?D6?C:D2C86=@32?83E?H:5:567:?:C:2?C63282:;E=296?6B8:3E?H:
A6B C2DE2? G2DE H2?8 6?63EC D682 =EBEC CE2DE 3:52?8 A6B C2DE2?
=E2C E3E?82? 2?D2B2 52H2 =E2C 52? :?D6?C:D2C 3E?H:

256. 66?E9: A6BC222?

257. N
#6D6B2?82?

258. :?D6?C:D2C 86=@32?8 3E?H: -
=E2C A6?2A2?8

259. 52H2 86=@32?8 3E?H: -
*E36B 3E?H: 36BEA2 C63E29 D:D: C6A6BD: A252 #/$#3
22?
62?42B2? 3E?H: 6 C682=2 2B29BD:?H2 86=@32?8 3E?H: 6B232D
52=2 D:82 5:6?C: 2= H2?8 C22 D6B;25: AE=2 A252 86=@32?8 4292H2
!?D6?C:D2C 3E?H: A252 3:52?8 A6BE22? 52=2 3@=2 H2?8 6:=:: ;2B:
;2B: 22? 6:=:: =E2C

260. 2?882A D:52 252 6?6B8: 3E?H: H2?8
9:=2?8 2D2E D6BC6B2A C6=22 A6B232D2?
!?D6?C:D2C3E?H:22?C62:?64:=;:2;2B2CE36B3E?H:6CE2DE
3:52?8 A6BE22? C62:? ;2E9 (6?8EB2?82? :?D6?C:D2C 3E?H: 2:32D
A6BD23292? ;2B2 52B: CE36B 3E?H: 66?E9: 9E3E?82? 36B:ED

271. N

273. #6D6B2?82?
;2B2 CE36B 3E?H: 6 A@C:C: 3:52?8

274. ;2B2 CE36B 3E?H: 6 A@C:C: 3:52?8

275. 6B52C2B2? '34#/##0 9 52A2D 5:?H2D22? 329G2 :?D6?C:D2C
3E?H: 36B32?5:?8 D6B32=: 56?82? E25B2D ;2B2 CE36B 3E?H: D6BC63ED
6 3:52?8 A6?56?82B2?
2. Taraf Intensitas (TI)
*6D:2A 29=E 5: 2=2 C66CD2 :?: 6:=:: 32D2C :?D6?C:D2C
A6?56?82B2?2D2C:?D6?C:D2C3E?H:H2?852A2D5:56?82BD6=:?822?EC:2
252=29 C63282: 36B:ED
1 bel (B) = 10 desibel (dB)
Tugas Anda 3.4
Berapakah rasio intensitas bunyi 90
dB terhadap intensitas bunyi 60 dB?

276. N
#$'.
!?D6?C:D2C52?+2B27!?D6?C:D2C52B:636B2A2*E36BE?H:
6/$'3608+ #3#(05'04+5#4 05'04+5#4/
+2B27:?D6?C:D2C3E?H:C63E29A6C2G2DA252;2B2

277. 252=29

278. 56B2A2D2B27
:?D6?C:D2C3E?H:A252;2B2

279. #7#$
:6D29E:

280. 5
!?D6?C:D2C3E?H:36B32?5:?8D6B32=:56?82?E25B2D;2B2

287. =@8 =@8
sumber gempa Malang
2 2
I r r
I I
I r r
300
6 10
Surabaya
68 Mudah dan Aktif Belajar Fisika untuk Kelas XII

293. 56?82?6?88E?22?'34#/##09 E?DE

295. 52?

296. 5:A6B@=69

298. =@8

300. =@8

305. Suatu gelombang gempa terasa di
Malang dengan intensitas 6 × 105 W/m2.
Sumber gempa berasal dari suatu
tempat yang berjarak 300 km dari
Malang. Jika jarak antara Malang dan
Surabaya sebesar 100 km dan ketiga
tempat itu membentuk segitiga
siku-siku dengan sudut siku-siku di
Malang, maka intensitas gempa yang
terasa di Surabaya adalah ....
a. 2 × 105 W/m2
b. 3 × 105 W/m2
c. 4,5 × 105 W/m2
d. 5,4 × 105 W/m2
e. 7,5 × 105 W/m2
UMPTN 1996
Pembahasan:
2 1 1
2 1
1 2 2
2
5
2 5
10
I
= 5,4 × 105 W/m2
Jawaban: d
300 km
100 km
Contoh 3.11
Pembahasan Soal
2 !?D6?C:D2C D6B64:= H2?8 2C:9 52A2D 6?:3E=2? B2?8C2?82?
A6?56?82B2? A252 D6=:?82 252=29 C636C2B
N

306. G2DD

307. H2?8 5:C63ED
C63282: !!
3 !?D6?C:D2C D6B36C2B H2?8 2C:92AE 5:D6B:2 D6=:?82 2?EC:2 D2?A2 B2C2
C2:D 252=29 C636C2B G2DD

308. H2?8 5:C63ED !
25: 32D2C A6?56?82B2? D6B6?529 252=29
N

309. G2DD

310. 52? 32D2C
:?D6?C:D2CD6BD:?88:252=29G2DD

311. +2B27:?D6?C:D2C

312. C632?5:?856?82?
=@82B:D2A6B32?5:?82?2?D2B2:?D6?C:D2C3E?H:52?92B82232?8:?D6?C:D2C
3E?H: H2?8 D6B56?82B 52? 6:=:: C2DE2? 56C:36= 5 *642B22D62D:C
9E3E?82? 2?D2B2

313. 52?

314. 5:DE=:C
=@8

316. #6D6B2?82?

317. D2B27 :?D6?C:D2C 5

318. :?D6?C:D2C 3E?H: -

319. N

320. -

321. :?D6?C:D2C 232?8 A6?56?82B2?
6B:ED :?: 52D2 :?D6?C:D2C 52? D2B27 :?D6?C:D2C 52B: 3636B2A2 CE36B
3E?H:
32?8A6?56?82B2?
Q
N

322. 32?8B2C2C2:D

323. *:B:?6A252;2B2
Q
N

324. $2=E=:?D2CB22:
Q
N
(6B422A2?3:2C2A252;2B2
4

325. Q
N
)25:@A6=2?
Q
N
:C:3:C:

326. Q
N
Sumber: College Physics, 1980

327. Gelombang Bunyi 69

332. =@8

335. =@8

339. 5
=@8
N

340. 5

341. =@8

342. 25:D2B27:?D6?C:D2C3E?H:A252;2B2

343. 252=29
5
:2 D6B52A2D CE36B 3E?H: H2?8 =63:9 52B: C2DE D2B27 :?D6?C:D2C
D@D2=?H2 52A2D 5:6D29E: 56?82? 6?88E?22? A6BC222? 36B:ED
*63E29CE36B3E?H:6?892C:=2?D2B27:?D6?C:D2CC636C2B
56B2A2D2B27
:?D6?C:D2CH2?85:92C:=2?;:2D6B52A2D
CE36B3E?H:H2?8C2252?36B3E?H:
A252C22D36BC222?
#7#$
:6D29E:

344. 5
,?DEC63E29CE36B3E?H:

345. =@8

347. =@8

349. ,?DE
3E29CE36B3E?H:

350. Q

351. 22+!
=@8

353. =@8

355. =@8
5
Contoh 3.12

356. ?

357. =@8
N
#6D6B2?82?

358. D2B27 :?D6?C:D2C @=69 3E29 CE36B
32?H2?H2 CE36B

359. D2B27 :?D6?C:D2C @=69 3E29 CE36B
Kata Kunci
• energi gelombang bunyi
• intensitas gelombang
• taraf intensitas
• batas ambang pendengaran
*63E29CE36B3E?H:6:=::D2B27:?D6?C:D2CC636C2B

360. 5:2
3E29CE36B3E?H:H2?8C2236B3E?H:
C6B6?D236B2A2D2B27:?D6?C:D2C3E?H:H2?85:92C:=2?

361. 6B2A2A6B32?5:?82?:?D6?C:D2C5E2CE36B3E?H:;:2
D2B27:?D6?C:D2C?H25
*63E29 CE36B 3E?H: D:D: 56?82? 52H2

362. G2DD
62?42B2? 86=@32?8 3E?H: 36BEA2 86=@32?8
C76B:C 3@=2 +6?DE2? D2B27 :?D6?C:D2C 3E?H: H2?8
5:56?82B @=69 C6C6@B2?8 A252 ;2B2
6D6B 52B:
CE36B3E?H:D6BC63ED

363. N

364. G2DD

365. *63E29CE36B3E?H:6:=::D2B27:?D6?C:D2C36==
:2
3E29CE36B3E?H:H2?8C2236B3E?H:C642B2
C6B6?D2 36B2A229 D2B27 :?D6?C:D2C 3E?H: H2?8
5:92C:=2?
$5#0#4
*63E29CE36B3E?H:62?42B2?6?6B8:6C682=2
2B29A23:=2;2B2A6?56?82BD6B9252ACE36B3E?H:
5:3E2D6?;25:2=:C6E=236B2A2A6?8EB2?82?D2B27
:?D6?C:D2C3E?H:H2?8D6B56?82B
Tes Kompetensi Subbab F
'3,#-#0.#*#.#/$6-6.#5+*#0

366. Rangkuman
6=@32?83E?H:252=2986=@32?8=@?8:DE5:?2=H2?8
52A2D6B232D52=265:EI2DA252D42:B52?82C

367. 6A2DB232D3E?H:5:E52B236B82?DE?8A252;6?:C
A2BD:6=A636?DEE52B2H2?85:?H2D22?56?82?
$
C652?82? 5: 52=2 I2D A252D 36B82?DE?8 A252
@5E=EC.@E?852?2CC2;6?:CI2D
$
52AE?5:52=2I2D42:B36B82?DE?8A252@5E=EC
E=52?2CC2;6?:CI2D42:B
$
+:?88:B6?529?2523E?H:36B82?DE?8A2527B6E6?C:
3E?H:#E2D3E?H:36B82?DE?8A2522A=:DE5@86D2B2?
E5:@C@?:252=293E?H:H2?836B7B6E6?C:2?D2B2

368. IC2A2:56?82?

369. I!?7B2C@?:252=29
3E?H:H2?836B7B6E6?C:5:32G29

370. IC652?82?
E=DB2C@?: 252=29 3E?H: H2?8 36B7B6E6?C: 5: 2D2C

371. I
6=@32?83E?H:52A2D6?82=2:AB@C6C5:CA6BC:
B67B2C:B67=6C:5:7B2C::?D6B76B6?C:52?A@=2B:C2C:
!?D6B76B6?C:86=@32?83E?H:D6B;25:;:23652=:?D2C2?
86=@32?8?H26BEA22?6=:A2D2?3:=2?82?3E=2D
52B:C6D6?829A2?;2?886=@32?83E?H:
!

372. (6BC222?CEA6BA@C:C:86=@32?83E?H:

373. 4@C

374. C:?

375. B6E6?C:52??25252C2BA25252G2:5:?H2D22?56?82?
70 Mudah dan Aktif Belajar Fisika untuk Kelas XII
A6BC222?

376. C652?82? 7B6E6?C: ?252 2D2C 6 A252 52G2:
5:?H2D22?56?82?A6BC222?

377. (252A:A2@B82?2D6B3E27B6E6?C:?2522D2C6
5:?H2D22?56?82?A6BC222?
$

378. C652?82?A252A:A2@B82?2D6BDEDEA7B6E6?C:?252
2D2C65:?H2D22?56?82?

379. $
E3E?82? A2?;2?8 @=@ E52B2 D6B9252A
A2?;2?8 86=@32?8 3E?H: A252 A6B:CD:G2
B6C@?2?C:@=@E52B2252=29

380. 2=2A6B232D2??H286=@32?83E?H:6:?529
2?6?6B8:C636C2B

384. 56?82?252=29
2A=:DE5@86=@32?8

385. *62:?;2E9;2B2CE36B3E?H:D6B9252AA6?56?82B
:?D6?C:D2C3E?H:22?C62:?64:=
!?D6?C:D2C3E?H:5:?H2D22?56?82?A6BC222?
=@8

387. :2D6B52A2D3E29CE36B3E?H:D2B27:?D6?C:D2C
3E?H:D@D2=?H25:?H2D22?56?82?A6BC222?

388. ?

389. =@8

390. Gelombang Bunyi 71
Peta Konsep
6A2D)232D #=2C:7:2C:
*:72D*:72D
6=@32?8E?H:
6=@32?8E?H:
/2D(252D
$
/2D2:B
$
2C
$
!?D6B76B6?C:
(62?DE=2?
:7B2C:
(6=2H2?82?
!?D6?C:D2CE?H:
+2B27!?D6?C:D2C
;:2 CE36B
3E?H:?H2 32?H2
63292C
'.1/$#0)608+
63292C

391. =@8
63292C
+:?88:E?H:
#E2DE?H:
-2B?2E?H:
Refleksi
Setelah mempelajari bab ini, Anda tentu dapat
mengetahui sifat-sifat dasar gelombang bunyi dan
klasifikasi gelombang bunyi serta dapat menjelaskan
peristiwa resonansi pada pipa organa. Dari materi bab
ini, bagian manakah yang Anda anggap sulit? Coba
diskusikan dengan teman atau guru Fisika Anda.
Pada bab ini pula, Anda telah mempelajari manfaat
dari gelombang bunyi, seperti untuk mengukur
kedalaman laut. Coba Anda sebutkan manfaat lain yang
Anda rasakan setelah mempelajari bab ini.
52=2

392. (252CE2DEC22DD6B=:92D:=2D52?
56D:6E5:2?
D6B56?82B CE2B2 8E?DEB?H2 :2 36C2B 646A2D2?
4292H2
Q
C52?646A2D2?3E?H:
C
;2B22?D2B2D6A2D2C2=:=2D52?A6?822D
2
5
Q
3
6
Q
4

393. *63E29 2=2D C@?2B 5:8E?22? E?DE 6?8EEB
652=22?=2ED*6=2?8G2DEH2?85:42D2D@=69C@?2B
E?DE86=@32?86B232D9:?882632=:=28:6
C@?2B252=29C6@?:246A2DB232D86=@32?85:
52=2 2:B =2ED 252=29
C 652=22? =2ED
D6BC63ED252=29
2
5

394. 3
6
4
E2 3E29 CE36B 3E?H: C6A6BD: D2A2 A252 8232B
36B:ED 36B86D2B C642B2 @96B6? E?H: H2?8 ?H2B:?8
5:92C:=2?5:;:2

395. 6?82?6?2:2?C642B2
A6B=292?=292? 3E?H:D6B=6295:56?82B6D:2 N

396. 252=29

397. 4
452?
4:246A2DB232D
3E?H:5:E52B2
C36C2B7B6E6?C:3E?H:252=29
2
I 5
I
3

398. I 6
I
4
I
E23E29#! 52?5:=6D22?C6A6BD:A252
8232B 36B:ED +6B?H2D2 A252 56D6D@B D6B;25:
:?D6B76B6?C:2C:E@B56A6BD22:2646A2D2?
3E?H:5:E52B2
C7B6E6?C:86=@32?83E?H:
D6BC63EDD6BC63ED252=29
9 m
2 I 5
I
3
I 6
I
4 I
%@5E=ECE=CE2DEI2D42:BH2?86:=::2CC2;6?:C
8B2 4
252=29

399. Q

400. 6A2DB232D
86=@32?852=2I2D42:BD6BC63ED252=29
2
C 5
C
3

401. C 6
C
4

402. C
72 Mudah dan Aktif Belajar Fisika untuk Kelas XII
*63E29 CE36B 3E?H: 36B7B6E6?C: I 36B86B2
=2?8CE?862B29C6@B2?8A6?56?82B56?82?6=2;E2?
2=: 6=2;E2? 3E?H: B6E6?C: 3E?H: H2?8
5:D6B:2?H2252=29
2
I 5
I
3 I 6
I
4 I
1#.!9!
?52C652?836B86B26?562D:C63E29CE36B3E?H:
*D:5236B86B2H2?836B252;2E95:56A2??5252?
C652?862?42B2?3E?H:36B7B6E6?C:
6C682=2
2B2982;2E95:36=22?8?52D6B52A2DC63E29
5:?5:?8 A62?DE= E?H: H2?8 ?52 56?82B
=2?8CE?852B:*56?82?7B6E6?C:C52?H2?836B2C2=
52B: A2?DE=2? 5: 56?82? 7B6E6?C: 5 6D:2
36B:?D6B2C:5:D6=:?82?52252=29
2 D:5222?6?:3E=2?=2H2?82?2B6?2
C5
3 D:5222?6?:3E=2?=2H2?82?2B6?2
C5
4 22?6?:3E=2?=2H2?82?52?66?E9:
C5
5 22?6?:3E=2?=2H2?82?52?66?E9:
C
5
6 22?6?:3E=2?=2H2?82?52?66?E9:
C5
*63E29CE36B3E?H:36B86B256?82?646A2D2? C
6?E;E6A6?56?82BH2?85:2C69:?8827B6E6?C:
H2?85:56?82B@=69A6?56?82B252=29:2CE36B
3E?H:D6BC63ED5:2C652?82?A6?56?82B36B86B2
56?82? 646A2D2? C 6?562D: CE36B 3E?H:
7B6E6?C:H2?85:56?82B@=69A6?56?82B252=29

403. :2
46A2DB232D3E?H:5:E52B2$ CA6B32?5:?82?

404. 252=29
2 5 N

406. $
3 N
$
6

408. $
4
$
*6@B2?8A6?6B32?8H2?8A6C2G2DD6B32?8?H26?E;E
6 6?2B2 32?52B2 6?56?82B 3E?H: C:B:?6 6?2B2
56?82?7B6E6?C:

409. I:2C22D:DEC:B:?6D6BC63ED
62?42B2?3E?H:56?82?7B6E6?C:
I52?
46A2D B232D 3E?H: 5: E52B2
C 646A2D2?
A6C2G2DD6B32?8D6BC63ED252=29
2
;2 5

411. ;2
3

412. ;2 6

413. ;2
4

414. ;2
S
S2
r1
r2
P
40 m
A
B
D
Tes Kompetensi Bab 3
+.+*.#*4#.#*4#56,#7#$#08#0)2#.+0)5'2#5#0-'3,#-#0.#*2##$6-6.#5+*#0

415. Gelombang Bunyi 73
(6=2H2?82?3E?H:D6B;25:2B6?2252?H2:?D6B76B6?C:
2 =63:952B:

416. 86=@32?8H2?8C227B6E6?C:?H2
3

417. 86=@32?8H2?836B=2G2?2?2B2986D2B?H2
4

418. 86=@32?8H2?8C227B6E6?C:?H2
5

419. 86=@32?8H2?836C2B36527B6E6?C:?H2
6

420. 86=@32?8H2?864:=36527B6E6?C:?H2
:25E23E29CE36B3E?H:2C:?82C:?856?82?
7B6E6?C:

421. I52?

422. I36B3E?H:C6B6?D2
22?D:3E=A6=2H2?82?3E?H:56?82?7B6E6?C:
2

423. I 5

424. I
3 I 6

425. I
4 I

426. *6ED2C52G2:6?892C:=2?B6C@?2?C:A6BD22A252
4:2A2?;2?82G2D

427. 452?36B86D2B
A252?2522D2C65E246A2DB232D86=@32?8DB2?C
F6BC2=52=22G2D252=2946A2DB232D3E?H:5:
E52B2
C
2

428. C
3
C
4
C
5

430. C
6 C
E23E2952G2:32;2H2?8:56?D:636B:2??252
52C2B56?82?7B6E6?C:
I:2D682?82?52=2
C2=29C2DE52G2:5:D2329

431. 7B6E6?C:A6=2H2?82?
H2?8D6B;25:252=29
2
I 5 I
3

432. I 6 I
4 I
*63E29D23E?886=2CB6C@?2?C:H2?836B:C:2:B6:=::
=E2CA6?2A2?8
4

433. (252A@C:C:D6BC63EDD6B;25:
B6C@?2?C:A6BD22*6;E=29
4
2:B5:3E2?86=E2B
C69:?882D6B;25:B6C@?2?C:65E2:26=2;E2?3E?H:
5:E52B2
C7B6E6?C:82BAED2=2H2?85:A22:
252=29
2
I 5
I
3
I 6
4
I
(252A6B4@322?%6=565:8E?22?C6ED2C36?2?8H2?8
A2?;2?8?H26D6B52?36B2CC28B2:23632?
C636C2B

434. 8 5:82?DE?82? A252 36?2?8 D6BC63ED
646A2D2?A6B232D2?86=@32?8A25236?2?8252=29
C

435. 2 C 5

436. C
3
C 6
C
4

437. C
*6ED2C52G2:6?892C:=2??25252C2B:252G2:
D6BC63ED5:A6?562?4D2?A26?8E329D682?82?
5:92C:=2?7B6E6?C:

438. :252G2:5:A6?562?

439. 4=28:7B6E6?C:H2?85:92C:=2?252=29
2 5
3

440. 6

441. 4
*6ED2C52G2:H2?8A2?;2?8?H2
452?36B2CC2
8B25:;6A:D65E2E;E?8?H252?5:B6?D2?82?56?82?
D682?82?
B6E6?C: ?252 2D2C A6BD22 H2?8
5:92C:=2?252=29
2

442. I 5
I
3
I 6
I
4

443. I
1,2 m
f = 340 Hz
W
#6D:2 82BAED2=2 5:86D2B2? A252 52G2: D6B;25:
86=@32?8 CD2C:@?6B C6A6BD: D2A2 A252 8232B
#646A2D2?B232D86=@32?8A25252G2:252=29
2

444. C 5
C
3

445. C 6
C
4
C
*63E29A:A2@B82?2D6BDEDEA6:=::A2?;2?8
4
:246A2DB232D3E?H:5:E52B2

446. C36C2B7B6E6?C:
?2522D2C65E2252=29
2

447. I 5
I
3
I 6 I
4 I

448. 252 2D2C A6BD22 A:A2 @B82?2 D6B3E2 H2?8
A2?;2?8?H2
4 36B6C@?2?C: 56?82? A:A2 @B82?2
D6BDEDEA:2A252C22D36B6C@?2?C:;E=29C:AE=A252
65E2A:A2C22A2?;2?8A:A2@B82?2D6BDEDEAD6BC63ED
52=24252=29
2

449. 5
3
6
4
! #810

450. (252A:A2@B82?2D6B3E2?2522D2C65E25:92C:=2?
A2?;2?886=@32?8C636C2B %52?A252A:A2@B82?2
D6BDEDEA?2522D2C65E25:92C:=2?A2?;2?886=@
32?8C636C2B:2A2?;2?865E2A:A2C22?:=2:
A6B32?5:?82?52?%252=29
2

451. 3
4
5
6

453. +2B27:?D6?C:D2C3E?H:C63E296C:?B2D2B2D2
5
:2
6C:?5:9:5EA2?36BC22D2B27:?D6?C:D2C?H2
252=29
2

454. 5
3
5
4
5
5 5
6
5

456. :2C63E29C6A652@D@B6=6G2D:C6C6@B2?8@D@B
D6BC63ED22?6?:3E=2?D2B27:?D6?C:D2C+!C636C2B
5:2@B2?8D6BC63ED5:=6G2D:
C6A652@D@B;6?:C
H2?8C22C62=:8ECD2B27:?D6?C:D2C?H2252=29
2 5 5
5
3
5 6
5
4
5

457. +2B27 :?D6?C:D2C 3E?H: C63E29 6C:? 252=29
5
56?82?24E2?:?D6?C:D2C232?8A6?56?82B2?C636C2B
N

458. - :2D2B27:?D6?C:D2C5:52=2BE2?8A23B:
H2?86?88E?22?C6;E=296C:?D6BC63ED252=29
5;E=296C:?H2?85:8E?22?252=29
*63E2982BAED2=236B7B6E6?C:
I5:86D2B2?5:
A6BE22?D23E?8B6C@?2?C:(252C22D@=@E52B2
6?42A2:6D:?88:2?4D6B;25:B6C@?2?C:H2?8
A6BD226B2A22946A2DB232D3E?H:C22D:DE

459. *6ED2C 2G2D H2?8 A2?;2?8?H2
4 5::2D 65E2
E;E?8?H2#6E5:2?2G2D5:86D2B2?=@?8:DE5:?2=
6A2DB232D86=@32?8H2?85:92C:=2?
C
%@5E=EC.@E?82G2DQ

460. :DE?8=29
2 7B6E6?C:86D2B?H2
3 2CC2;6?:C2G2D
%@3:= 6?562D: A6?822D 5:2 56?82?
646A2D2?
C C23:= 63E?H:2? C:B6?6
36B7B6E6?C:
I (252 C22D :DE ;E82 @3:=
6?562D: 52B: 2B29 H2?8 36B=2G2?2? 56?82?
A252 646A2D2?

461. C C23:=63E?H:2? C:B:?6
36B7B6E6?C: I:246A2DB232D3E?H:5:E52B2
C22D:DE
C36B2A2297B6E6?C:=2H2?82?H2?8
5:56?82B@=69
*6ED2C2G2D32;2H2?82CC2?H2852?A2?;2?8
5:36B:D682?82?+6?DE2?
2 46A2D B232D A2?;2?8 86=@32?8 DB2?CF6BC2=
C6A2?;2?82G2D
3 A2?;2?886=@32?852?7B6E6?C:?25252C2B?H2
4 7B6E6?C:?2522D2C6C2DE52?65E2
74 Mudah dan Aktif Belajar Fisika untuk Kelas XII
B6E6?C:?2522D2CA6BD2252B:A:A2@B82?2D6B3E2
I :2 46A2D B232D 3E?H: 5: E52B2
C
9:DE?8=29
2 7B6E6?C:?25252C2B?H2
3 7B6E6?C:?2522D2C6D:82
6A2DB232D3E?H:52=2C63E29A:A2@B82?2252=29
C:27B6E6?C:?25252C2BA:A2@B82?2252=29

462. I36B2A2A2?;2?8:?:EA:A2@B82?2E?DE
2CEC
2 A:A2@B82?2D6B3E2
3 A:A2@B82?2D6BDEDEA
E2ED2C52G2:32;2C6;6?:C636B:2??25252C2B

463. I:2A2?;2?8C2=29C2DE52G2:5:D2329

464. 36B2A2297B6E6?C:=2H2?82?H2?8D6B;25:
E2ED2C52G2:32;2H2?8:56?D:636B:2??252
52C2B56?82?7B6E6?C:
I:2D682?82?52=2
C2=29 C2DE 52G2: 5:D2329

465. 36B2A2 7B6E6?C:
=2H2?82?52G2:H2?8E?8:?
*66@B D2G@? H2?8 6?56?8E?8 A252 ;2B2
6:=::D2B27:?D6?C:D2C
5:2252
D2G@?
6?56?8E?8A252;2B2%D2B27:?D6?C:D2C?H2
5
D6?DE2?;2B2%
(252C63E29D23E?8B6C@?2?C:D6B52A2D@=@E52B2
A252 *6=:C:9 A2?;2?8 @=@ B6C@?2?C:
4
#646A2D2? 3E?H: A252 CE9E
L 252=29
C
:DE?8;:27B6E6?C:B6C@?2?C:
I
#7#$.#*2'35#08##0$'3+-65'0)#05'2#5
2

466. 5

467. 3
6
4

468. +2B27 :?D6?C:D2C 3E?H: A252 C63E29 ;6?56=2 D6B3E2
H2?8 =E2C?H2

469. 252=29
5 :2 ?:=2: 232?8
3E?H:
N- 4

470. 52H22ECD:H2?82CE6=2=E:
;6?56=2D6BC63ED252=29
2
N-
3
N

471. -
4
N
-
5
N-
6
N-