radiasi benda hitam

1. Matahari merupakan sumber energi yang utama bagi Bumi. Matahari
memberikan energi melalui radiasi gelombang yang dipancarkannya.
Radiasi Benda Hitam Radiasi Benda Hitam
Hasil yang harus Anda capai:
menganalisis berbagai besaran fisis dan gejala kuantum dan batas-batas
berlakunya relativitas Einstein dalam paradigma Fisika Modern.
Setelah mempelajari bab ini, Anda harus mampu:
menganalisis secara kualitatif gejala kuantum yang mencakup hakikat dan sifat-sifat
radiasi benda hitam, serta penerapannya.
A. Pengertian Radiasi
Benda Hitam
B. Dualisme
Gelombang
Partikel
'2D292B:6BEA22?CE36B69:5EA2?5:E: ?6B8:I2?85:A2?42B2?
'2D292B:632?DEC6E2DE3E92?36B=@B@7:=E?DE6=2E2?7@D@C:?D6C:C
I2:DE AB@C6C A63E2D2? 22?2? -E3E92? 6BEA22? CE36B 22?2?
ED22328:2?EC:252?96G2? $25:C642B2D:52=2?8CE?82?EC:252?96G2?
36B82?DE?8 A252 6?6B8: I2?8 5:A2?42B2? '2D292B: ,6=2:? :DE 6?6B8: I2?8
5:A2?42B2?'2D292B:63E2DCE9E5:E:D6D2A92?82DD:52D6B=2=E5:?8:?
C69:?882 69:5EA2? 5: E: D6D2A D6B;282 *6B?292? ?52 36BA::B 36B2A2
36C2B6?6B8:I2?85:A2?42B2?'2D292B:2D2E36B2A2CE9E'2D292B:C69:?882
6:=:: 6?6B8: I2?8 C2?82D 36C2B '6?EBED 3636B2A2 A6?6=:D:2? CE9E 5:
A6BE22?'2D292B:C6:D2B L A229?523:C26?5E823282:2?2
42B2:=EG2?D6BC63ED6?89:DE?8CE9E'2D292B:2=6?2B:=2:??I2252=29
B25:2C: I2?8 5:A2?42B2?'2D292B: A229 C:?2B '2D292B: A252 C:2?8 92B:
5:2?882A 36B3292I2 328: E=:D 5:2B6?22? B25:2C:?I2 =63:9 D:?88: A229
9E3E?82?2?D2B2B25:2C:I2?85:A2?42B2?52?CE9E'2D292B:
*6BD2?I22?A6BD2?I22? D6BC63ED 52A2D ?52 ;2G23 C6D6=29 ?52
6292: @?C6A B25:2C: 36?52 9:D2 2=2 323 :?: ?52 22?
6?52A2D2? 3636B2A2 76?@6?2 2=2 I2?8 C636?2B?I2 6BEA22?
2A=:2C: 52B: @?C6A 7:C:2
175
Bab
7
Sumber: CD Image

2. Tes Kompetensi Awal
!*'*1922*25*1/6.0437*5 ).7.*3).820*6/031-741741'*6.098)12'90918.-3

3. $:2?526?;6EB5E22:?32C29I2?836BG2B?2
9:D2 52? AED:9 5: 32G29 C:?2B '2D292B: 2:?
2?229 I2?8 22? =63:9 46A2D 6B:?8 $6=2C2?
6?82A256::2?
A2I2?85:2CE556?82?36?529:D2C6AEB?2
A. Pengertian Radiasi Benda Hitam
1. Radiasi Benda Hitam
?52 D6=29 36=2;2B 5: 6=2C 1 D6?D2?8 A2?42B2? 2D2E B25:2C: @=69
CE2DE 36?52 ':C2=?I2 9E3E?82? 2?D2B2 32?I2?I2 6?6B8: I2?8
5:A2?42B2?52?CE9EI2?85::=::CE2DE36?52 ,642B2C656B92?2?52
52A2D 6=2E2? A6?822D2? 6=2=E: C63E29 68:2D2? I2?8 C6B:?8
5:=2E2? ':C2=?I26D:2?5236B@=29B282A252A28:92B:I2?846B29
?52 22? 6B2C22? 252?I2 2=@B I2?8 5:A2?42B2? @=69 4292I2
'2D292B: 6 DE3E9 %6D:2 ?52 2CE 6 52=2 BE2?82? 22? D6B2C2
329G2CE9EBE2?82?6?:?82D 2=D6BC63ED6?E?;E2?252?I22=@B
I2?85:A2?42B2?52B:DE3E9ED6B9252A=:?8E?82?56?82?42B2B25:2C:
@?D@9 D6BC63ED 63ED:2? 329G2 36?52 22? 62?42B2?
B25:2C:6=6DB@28?6D:;:26:=::CE9ED:?88: +25:2C:6=6DB@28?6D:
I2?8 5:A2?42B2? @=69 36?52 5:C63ED +, -+%
-29E29?522A2I2?85:2CE556?82?36?529:D2

4. '!-
%! ,.-. ,,- 1' )- '1+) ,. +, $%(+ 1' ' '
' -. ,,- -+,.- ,EA2I2 ?52 52A2D =63:9 6292: D6?D2?8
36?52 9:D2 A6B92D:2? 8232B 36B:ED
*2522'65:A6B=:92D2?C63E29@D2I2?8D6B3E2D52B:=@82
I2?852A2D5:2?882AC63282:36?529:D2C6AEB?252?C2=29C2DEC:C:?I2
5:3E2D =E32?8 292I2 I2?8 2CE 6=2=E: =E32?8 5:A2?DE=2? D6BEC
6?6BEC @=69 5:?5:?8 @D2 52? 92A:B 52A2D 5:A2CD:2? D:52 252 =28:
4292I2 I2?8 6=E2B #?: 2BD:?I2 =E32?8 D6=29 36B7E?8C: 6?I6B2A C6E2
B25:2C: 2=@B I2?8 252 +25:2C: 4292I2 I2?8 6=E2B 52B: 52=2 @D2
9:D2 6=2=E: C63E29 =E32?8 36B2C2= 52B: @C:=2D@B@C:=2D@B 92B@?: I2?8
36B86D2B 5: 52=2 @D2 56?82? @5EC 86D2B D6BD6?DE D@2D@ A252
5:?5:?8 @D2 22? 6?I6B2A 6?6B8: A2?2C 52? 36B86D2B D@2D@ :?:
22? 36B=2E C63282: @C:=2D@B 92B@?: I2?8 6?:3E=2? 86=@32?8
6=6DB@28?6D: !6=@32?8 6=6DB@28?6D: I2?8 5:D:3E=2? @=69
@C:=2D@B 22? 5:A2?DE=2? 36BE=2?8E=2?8 @=69 5:?5:?8 @D2 52?
636?DE 86=@32?8 36B5:B:
2C:= 6CA6B:6? 6?E?;E2? 329G2 :?D6?C:D2C B25:2C: D6B2=
36B32?5:?8 =EBEC 56?82? A2?82D 6A2D CE9E 36?52 ,62:? D:?88: CE9E
C63E29 36?52 C62:? 36C2B AE=2 6?6B8: 2=@B I2?8 5:A2?42B2? ,6=2:?
:DE 6?6B8: 2=@B 52? :?D6?C:D2C B25:2C: D6B2= C2?82D 36B82?DE?8 A252
@?5:C: 36?DE 52? A6BE22? I2?8 5::=:: 36?52 '6?EBED !8*+3
418233 :?D6?C:D2C B25:2C: D6B2= CE2DE 36?52 5:?I2D22? 56?82?
176 Mudah dan Aktif Belajar Fisika untuk Kelas XII
M

5. Gambar 7.1
Cahaya yang masuk ke dalam
kotak yang dianggap sebagai
benda hitam sempurna, akan
dipantulkan terus-menerus oleh
dinding kotak.
A229C6D:2A36?52C6=2=E62?42B2?6?6B8:
A2I2?85:2CE55E2=:C686=@32?8A2BD:6=
A2I2?85:2CE56767@D@=:CDB:52?676@AD@?
,63ED2?;E82D@@9D@@9A6?6E2?86;2=2D6BC63ED

6. Ingatlah
Dalam SI, suhu menggunakan satuan
derajat Kelvin.
Ingatlah
Radiasi Benda Hitam 177
%6D6B2?82?
6:C:F:D2C36?52

7. E?DE36?529:D2C6AEB?2

8. CE9E %
@?CD2?D2,D672?@=DJ2??P

9. M0
%
)=69 2B6?2 :?D6?C:D2C 252=29 6?6B8: I2?8 I2?8 5:A2?42B2? D:2A
C2DE2? G2DE 52? D:2A C2DE2? =E2C 22 :?D6?C:D2C B25:2C: D6B2= 52A2D
;E82 5:?I2D22? C63282: 52I2 A6B C2DE2? =E2C
52? M
%6D6B2?82?
:?D6?C:D2C B25:2C: D6B2= 0
52I2 0
=E2C A6BE22? 36?52
6?82? 6?CE3CD:DEC:2? *6723 ? 6 *6723 ?
22 52I2 B25:2C: I2?8 5:A2?42B2? 36?52 22? 6:=:: A6BC222?
M
*252CE9EBE2?8C6:D2B
LB25:2C:D6B2=I2?85:A2?42B2?36?52
D:52 52A2D D6B=:92D @=69 2D2 2? D6D2A: 36?5236?52 D6BC63ED A252
CE9E
L 52A2D D6B=:92D 2= D6BC63ED 5:C63232? 36?5236?52 :DE
62?DE=2? 4292I2 $25: ;:2 ?52 :?8:? 6?822D: B25:2C: D6B2=
C2;2 92BEC 6?88E?22? 36?52 I2?8 D:52 62?DE=2? 4292I2
:C2=?I2 36?5236?52 I2?8 36BG2B?2 9:D2 6?52 9:D2 6?I6B2A
C6=EBE9 B25:2C: I2?8 52D2?8 6A252?I2 2= :?: 52A2D ?52 22D: 6D:2
C6C6@B2?8 62?2C2? C632D2?8 36C: *252 CE9E 5: 32G29
L 36=E
D2A2 CA6DBE G2B?2 I2?8 5:D:3E=2? 52B: 36C: :DE C6D6=29 CE9E
5:?2:2? 52? 36C: E=2: 632B2 22? E=2: D2A2 A6BE3292?
CA6DBE G2B?2 36BC222? 56?82? 6?2:2? CE9E
Contoh 7.1
,63E2936?526:=::CE9EC636C2B
L $:2@?CD2?D26:C:F:D2C36?52D6BC63ED
D6?DE2?:?D6?C:D2CB25:2C:I2?85:A2?42B2?
;'
:6D29E:
%%
P

10. M0
%
6B52C2B2?*6723?22?5:A6B@=69
P

11. M0
%%

12. 0
$25::?D6?C:D2CB25:2C:D6B2=I2?85:A2?42B2?36?52D6BC63ED252=29

13. 0
Contoh 7.2
%2G2DCA:B2==2AEA:;2B6:=::=E2CA6BE22?
52?CE9E?I2

15. L
:2?52:2?329G252B:6?6B8:=:CDB:I2?85:92?D2B2?A252=2AE5:B25:2C:2?
52=236?DE2=@B52?2G2DA:;2B36BC:72DC6A6BD:36?529:D2 6B2A22A6B62BEC
I2?86?82=:B52=2=2AEI2?85:9E3E?82?56?82?CD@A@?D236BD682?82?
/282B=2AED6BC63ED52A2D36B7E?8C:
Dalam kehidupan sehari-hari tidak
ada benda yang dapat menyerap
seluruh radiasi yang mengenainya.

17. 0
/
2. Spektrum Radiasi Benda Hitam
$:2 CE2DE 36?52 A252D 5:A2?2C2? 36?52 D6BC63ED 22? 62?
42B2? B25:2C: 2=@B 52=2 36?DE CA6DBE 86=@32?8 6=6DB@28?6D:
56?82? A2?;2?8 86=@32?8 52? 7B6E6?C: I2?8 36B3652 *252 CE9E I2?8
=63:9 D:?88: 22? D6B52A2D B25:2C: :?7B2 6B29 I2?8 D:52 52A2D 5:=:92D
D6D2A: 52A2D 5:B2C22? A2?2C?I2 2= :?: 52A2D 5:22D: A252 C6A@D@?8
=@82 I2?8 5:A2?2C2? 9:?882 6?42A2: CE9E
% @82 36BA:;2B
56?82? G2B?2 E?:?8 2D2E 6AED:9AED:92? +25:2C: 86=@32?8 I2?8
5:A2?42B2? 6E5:2? 5:=6G2D2? 6=2=E: 46=29 282B 5:A6B@=69 36B2C
86=@32?8 I2?8 C6A:D C6A6BD: D2A2 A252 2'6
6?82? 56::2? 86=@32?8 22? D6B5:CA6BC: 6?EBED A2?;2?8
86=@32?8 C6D:2A CA6DBE 6D6D@B I2?8 D6B=:92D A252 8232B 52A2D
5:86C6B86C6B 6?EBED CE5ED 56F:2C: 86=@32?8 D6B5:CA6BC: *6B4@322?
:?: 5:=2E2? A252 CE9E 36?52 9:D2 I2?8 36B36523652 *6?822D2?
A252 :?D6?C:D2C CA6DBE B25:2C: 6?892C:=2? 52D2 I2?8 5:DE?;E2?
A252 2'6
2'6
6?E?;E2? 329G2 2A23:=2 CE9E CE2DE 36?52 D6BEC
5:?2:2? :?D6?C:D2C B6=2D:7 52B: CA6DBE 4292I2 I2?8 5:A2?42B2??I2
36BE329 #?:6?I63232?A6B86C6B2?52=2G2B?2G2B?:CA6DBEI2?8
D6B22D:I2?852A2D5:8E?22?E?DE6?2C:BCE9ECE2DE36?52 -6B=:92D
;E82 A6B86C6B2? A2?;2?8 86=@32?8 2C:E 2C ,62:? D:?88:
CE9E CE2DE 36?52 2C C62:? 36B86C6B 6 2B29 A2?;2?8 86=@32?8
I2?8 =63:9 A6?56
82B ?52 =63:9 6292: EE *6B86C6B2? 0:6? A6B92D:2?
2'6 36B:ED
detektor
Gambar 7.2
celah
Percobaan untuk mengamati
spektrum radiasi benda hitam.
Warna
putih
kuning muda
kuning
oranye
merah-oranye
merah ceri
merah tua
baru tampak
Gambar 7.3
T ºC
1.500
1.400
1.300
1.200
1.100
1.000
900
800
700
600
500
Spektrum warna pijar suatu benda
panas berubah terhadap suhunya.
178 Mudah dan Aktif Belajar Fisika untuk Kelas XII
I (Wb/m2)
(m)
T2 T1
T1
benda hitam
prisma
spektrum
gelombang
Gambar 7.4
Grafik pergeseran panjang
gelombang maksimum pada
saat suhu berubah dari T1 ke T2.
;'
:6D29E:
=E2CA6BE22?
P

18. M
CE9EED=2

20. %

21. %6:C:F:D2C

22. 2?882A36?529:D2 P

23. M0
%
2I22=@BB25:2C:I2?85:A2?42B2?@=69=2AEA:;2B5:9:DE?86=2=E:*6723
?
I2:DE

24. P

25. M03
%P

26. M

27. %

28. 0
2I22=@BB25:2C::?:252=2952B:52I2=:CDB:I2?85:36B:2?6=2AEA:;2B
$25:

29. 0P=:CDB:
=:CDB:

30. 0

31. 0
-682?82?=:CDB:
F@=D
BEC=:CDB:I2?86?82=:B6=2=E:=2AEA:;2B5:9:DE?852B:BEEC52I2=:CDB:
Sumber: Physics, 1993
Sumber: Physics, 1993

32. Sumber: Fundamental Of Physics, 2001
Radiasi Benda Hitam 179
2B: 2'6 D6B=:92D 329G2 A2?;2?8 86=@32?8 :?D6?C:D2C
2C:E 36?52 I2?8 CE9E?I2 D:?88: =63:9 A6?56 52B: A2?;2?8
86=@32?8:?D6?C:D2C36?52I2?8CE9E?I2B6?529 !6;2=2A6B86C6B2? 2C
A252 B25:2C: 36?52 9:D2 5:C63ED EE *6B86C6B2? 0:6? ,642B2
2D62D:C EE *6B86C6B2? 0:6? 5:?I2D22? 52=2 A6BEEC2?
36B:ED
2C @?CD2? M
0:6? 6?6E2? 329G2 92C:= 2=: 2?D2B2 2C 52? CE9E ED=2
6BEA22?3:=2?82?@?CD2?C6A6BD:A252 *6723 ?52?3:=2?82?
@?CD2?A252A6BEEC2?EE*6B86C6B2?0:6?36B?:=2:
P

33. M%
EE*6B86C6B2?0:6?;E825:8E?22?E?DE6A6B:B22?CE9E
C63E29 3:?D2?8 56?82? 6=:92D G2B?2 4292I2 C63E29 3:?D2?8 CE9E
3:?D2?8 D6BC63ED 52A2D 5:AB65:C:2?
Contoh 7.3
,63E2936?525:A2?2C2?9:?88236BCE9E L -6?DE2?=29A2?;2?886=@32?8
2C:EB25:2C:D6B2=I2?85:A2?42B2?36?52D6BC63ED
;'
:6D29E: L
%
%
36B52C2B2?*6BC222?

34. M22?5:A6B@=69
2C
2C
%
P

35. M%
2C

36. %

37. %
$25:A2?;2?886=@32?82C:EB25:2C:D6B2=252=29P

38. M
I
Contoh 7.4
6B52C2B2?8B27::?D6?C:D2CB25:2C:
D6B9252A A2?;2?8 86=@32?8 C6A6BD:
T5:DE?;E2? A252 8232B 5: C2A:?8
1
T3282:2?2299E3E?82?2?D2B2CE9EED=2
2
T52?
3

39. ;'
2B:8B27:A2528232B5:C2A:?85:A6B@=69
329G2 EBED2? A2?;2?8 86=@32?8 E?DE :?D6?C:D2C B25:2C: 2C:E 252=29

40. 6B52C2B2?9EEA6B86C6B2?0:6?*6723?5:A6B@=69
2D2E
$25:

41. 5:A6B@=69

42. 3. Pendekatan Teori Rayleigh–Jeans
*252 D29E?

43. E?4E= A6BD2?I22? 3282:2?2 6?;6=2C2?
CA6DBE B25:2C: 36?52 9:D2 *6?822D2? 52? 6CA6B:6? I2?8 D6=29
5:=2E2? A252 2C2 :DE 6?4@32 6?42B: A6?;6=2C2? ,A6DBE B25:2C:
Tokoh
Max Planck
(1858 – 1947)
Max Planck dilahirkan di Kiel,
Jerman. Ia belajar di Munich dan
Berlin. Seperti banyak ahli fisika
lainnya, ia seorang pemain musik
yang pandai. Pada tahun 1900 M,
setelah 6 tahun belajar di Universitas
Berlin, ia menyatakan bahwa kunci
pemahaman radiasi benda hitam
adalah anggapan bahwa pemancaran
dan penyerapan radiasi terjadi dalam
kuantum energi hf. Penemuan yang
menghasilkan hadiah Nobel 1918 ini
sekarang dianggap sebagai tonggak
dari fisika modern. Walaupun selama
Hitler berkuasa, ia tetap tinggal di
Jerman. Ia memprotes perlakuan
Nazi kepada ilmuwan Yahudi dan
sebagai akibatnya ia harus
melepaskan kedudukannya sebagai
presiden Institut Kaiser Wilhelm.
Setelah perang dunia kedua, institut
tersebut diberi nama Institut Planck
dan ia kembali menjabat sebagai
presiden sampai akhir hayatnya.
m1 m2 m3

44. 36?529:D25:D6B2?82?@=6946) =1*.,-

45. M

46. 52?!.62*7
45;6) *37

47. M

48. *6BEEC2? 6B62 6?88E?22? D6@B:
7:C:2 =2C: C6A6BD: D6@B: :?6D: 82C
:%6=2C1#?52D6=296A6=2;2B:2D6B:A2?2C36?5236B9E3E?82?
56?82? 6?6B8: :?6D: @=6E= 82C -6@B: 6:A2BD:C: 6?I2D22? 329G2
6?6B8: D@D2= 82C 52=2 CE2DE BE2?82? D6BDEDEA 5:328: C642B2 6B2D2 6
C6D:2A @=6E= I2?8 D6B52A2D 5: 52=2 BE2?82? $:2 6?6B8: D@D2= C:CD6
252=29 52? 32?I2?I2 @=6E= I2?8 36B252 52=2 BE2?82? 252=29
6?6B8: B2D2B2D2 I2?8 5::=:: @=69 C6D:2A @=6E= 252=29
?6B8: :?:
D6B2?5E?852=236?DE6?6B8::?6D:C6D:2A@=6E= 2?D6D2A:D:52
36B2BD:C6E2@=6E=6:=::6?6B8:I2?8C22I2:DE (:=2:D6BC63ED
92?I2=29 6BEA22? ?:=2: B2D2B2D2
2'6

49. 6A6B=:92D2? C632B2? 646A2D2? I2?8 5::=::
@=6E= 82C ,632B2? 6?6B8: 646A2D2? 2B6?2 6?6B8: :?6D: C6=2=E
36B9E3E?82? 56?82? 646A2D2? =1*.,-*37 6=:92D 329G2 EBF2
C632B2? :DE C6BEA2 56?82? 92C:= I2?8 5:A6B@=69 A252 :?D6?C:D2C CA6DBE
B25:2C: D6B2= '6B62 36B2?882A2? 252 6:B:A2? 2?D2B2 C:72D A2?2C
36?52 52? B25:2C: D6B2= 6?82? A6?562D2? I2?8 6B62 =2E2?
=1*.,-*37 6A6B@=69 A6BEEC2? 329G2 :?D6?C:D2C B25:2C:
36B32?5:?8 D6B32=: 56?82? A2?82D 6A2D A2?;2?8 86=@32?8
.?DE I2?8 36C2B :?D6?C:D2C 22? C62:? 64:= A23:=2
6?562D: D2 9:?882 :?D6?C:D2C 22? 6?562D: ?@= 2= :?: C6CE2:
56?82?92C:=6A:B:C 2?D6D2A:2A23:=2 6?562D:?@=92=:?:C2?82D
6?I:A2?8 52B: 92C:= 6A:B:C I2?8 6?E?;E2? 329G2 :?D6?C:D2C
6?562D: ?@= 6D:2 C62:? 6?864:=
*6?I:A2?82? A6BC222? +2I=6:89 $62?C I2?8 C2?82D ;2E9 :?:
5:?222? N6?42?2 .=DB2 /:@=6DO 2B6?2 I2?8 64:= 36B252 52=2
G:=2I29 86=@32?8 E=DB2F:@=6D
2'6
6?E?;E2? 9E3E?82? :?D6?C:D2C 52? A2?;2?8
86=@32?8 2?D2B2 EBF2 +2I=6:89$62?C 52? EBF2 0:6? -6@B: %.*3
52A2D 6?6B2?82? CA6DBE A252 A2?;2?8 86=@32?8 I2?8 A6?56
D6D2A:6?I:A2?86D:26?6B2?82?A2?;2?886=@32?8I2?8A2?;2?8
,632=:?I2 D6@B: =1*.,-*37 52A2D 6?6B2?82? CA6DBE A252
A2?;2?886=@32?8I2?8A2?;2?8D6D2A:6?I:A2?86D:26?6B2?82?
A2?;2?8 86=@32?8 I2?8 A6?56
4. Teori Planck
-6@B: =2C: D6?D2?8 4292I2 C63282: 86=@32?8 6=6DB@28?6D:
52A2D 6?;6=2C2? 52B: 2?2 2C2= B25:2C: 2=@B D6D2A: D:52 3:C2 56?82?
D6A2D 6AB65:C:2? CA6DBE 4292I2 I2?8 5:A2?42B2? C63282:2?2
I2?8D6B22D:@=69 %.*3 -6@B: %.*32AE6?;6=2C2?B25:2C:36?52
9:D2E?DEA2?;2?886=@32?8I2?8A6?56D6D2A:8282=E?DEA2?;2?8
86=@32?8 I2?8 A2?;2?8 ,632=:?I2 D6@B: =1*.,-*37 36B92C:=
6?;6=2C2?B25:2C:36?529:D2E?DEA2?;2?886=@32?8I2?8A2?;2?8
D6D2A: 8282= E?DE A2?;2?8 86=@32?8 I2?8 A6?56
9:B?I2 A6?;6=2C2? I2?8 6E2C2? =29:B 52B: C6@B2?8 7:C:2G2?
$6B2? 13(0

50. M

51. #2 6?4@32 6=2E2? A6?562D2?
=2:? 56?82? 6?82;E2? CE2DE BEEC 6A:B:C 52? D6B?I2D2 C2?82D 4@4@
56?82? 92C:= A6?822D2??I2
v
n (v)
Gambar 7.5
Sebaran jumlah partikel yang
memiliki kecepatan (v).
Teori Rayleigh - Jeans
Teori Wien
Intensitas
Teori Planck
Panjang gelombang
Gambar 7.6
Perbandingan teori Wien, dan
teori Rayleigh-Jeans dengan
teori Planck yang memenuhi
data percobaan.
Tugas Anda 7.1
Carilah dari buku-buku tentang
formula yang digunakan Rayleigh-
Jeans untuk menjelaskan intensitas
radiasi benda hitam.
180 Mudah dan Aktif Belajar Fisika untuk Kelas XII

52. ke n =
4
3
2
1
4hf
3hf
2hf
1hf
Radiasi Benda Hitam 181
13(0 6?42B: 52C2B D6@B: E?DE BEEC 6A:B:C?I2 E2 3E=2?
6E5:2? :2 36B92C:= 63E2D 2CEC: I2?8 C2?82D 6?86;ED2? A252
C22D :DE I2:DE D6?D2?8 86D2B2? @=6E=@=6E= 5: A6BE22? 36?52
9:D2 13(0 6?86E22? A@CDE=2D?I2 C63282: 36B:ED

53. ?6B8: B25:2C: I2?8 5:A2?42B2? @=69 86D2B2? @=6E=@=6E=
@C:=2D@B 36?52 6BEA22? A26DA26D E2?D2 6?6B8: 6C2B?I2
6?6B8: 52=2 C6D:2A A26D 6BEA22? 6=:A2D2? 3:=2?82? 3E=2D CE2DE
36C2B2? NO I2:DE
?'! M
56?82? ' 252=29 3:=2?82? 2C=:

54. I2?8 5:C63ED 3:=2?82?
E2?DE 52? 252=29 7B6E6?C: 86D2B2? @=6E=@=6E= C652?8
2? ! 6BEA22? @?CD2?D2 *=2?4 I2?8 36C2B?I2
P

55. M $C
)=69 2B6?2 6?6B8: B25:2C: 36BC:72D 5:CB:D 5:2D22? 6?6B8:?I2
D6BE2?D:C2C: 52? 6?6B8: I2?8 5:A6B3@=692? 56?82? '

56. 5:C63ED D:?82D 6?6B8:
'@=6E=@=6E=6?I6B2A2D2E62?42B2?6?6B8:B25:2C:4292I2
52=2A26D5:CB:DI2?85:C63EDE2?DE2D2E7@D@? ?6B8:

57. 7@D@?
2B6?2 A6B36522? 5E2 D:?82D 6?6B8: C6A6BD: D2A2 A252 2'6
252=29
! M
$:2 @=6E=@=6E= 6?I6B2A
62?42B2?

58. 7@D@? D:?82D
6?6B8:?I236BD23292D2E36BEB2?8C636C2B! !282C2? 13(0 :?:
36B=2E E?DE 36?52 9:D2
2?82913(056?82?A@CDE=2D?I2329G26?6B8:@C:=2D@BD6BE2?D:C2C:
6BEA22? C63E29 D6B@3@C2? 36C2B 13(0 C6?5:B: 36BC22 :=EG2?
C62?82D2??I2D:526?I252B:92=:DE !282C2?*=2?45:2?882AC63282:
D@?882 2G2= 7:C:2 E2?DE
E n
0
0
Gambar 7.7
Tingkat-tingkat energi yang
diperkenankan untuk satu
molekul yang frekuensinya f.
$E=29 :?:E 7@D@? 4292I2 I2?8 A2?;2?8 86=@32?8?I2 ? E?DE
6?:3E=2?B2?8C2?82?F:CE2=A2522D2?@B2=252=29'

59. 7@D@?A6BC6@?
$:246A2DB232D4292I2P

60. C52?!P

61. M$CD6?DE2?=2952I2
4292I2D6BC63ED
;'
?6B8:4292I236B52C2B2?*6723?

62. 252=29
' ! '!
2I24292I2D6BC63ED52A2D5:D6?DE2?C63282:36B:ED
' !
- -

63. $C

64. C

65. 0

66. C

67. Contoh 7.5
Tantangan
untuk Anda
Perumusan Rayleigh-Jeans tidak
cocok diterapkan untuk radiasi
benda hitam pada daerah panjang
gelombang pendek. Dapatkah Anda
menduga, apa implikasi dari
persamaan Rayleigh-Jeans pada
daerah panjang gelombang pendek
untuk kehidupan di Bumi?

68. 5. Aplikasi Radiasi Benda Hitam untuk Mengukur Suhu
Matahari
'2D292B: 6BEA22? 3:?D2?8 I2?8 A2=:?8 562D 56?82? E:
;2B2?I2 C6:D2B

69. '2D292B: 62?42B2? 6?6B8: 2=@B
I2?8 C2?82D 36B8E?2 328: 69:5EA2? 5: E: ?6B8: D6BC63ED 36B2C2=
52B: B62C: 7EC: 9:5B@86? 5: 52=2 :?D: '2D292B: 2A2D29 ?52
632I2?82? 36B2A2 36C2B 6?6B8: I2?8 5:92C:=2? '2D292B: C69:?882
C2A2: ;2B2

70. 6?6B8: :DE 2C:9 252 36BEA2 4292I2 52?
2=@B
+25:2C:6?6B8:'2D292B:C2?82D36C2BC6A6BD:I2?8D6=29?52A6=2;2B:
#?D6?C:D2C B25:2C: :?: 36B32?5:?8 =EBEC 56?82? A2?82D 6A2D CE9E?I2
'6?EBED D6@B: B25:2C: I2?8 5:A2?42B2? :?: 6:=:: :?D6?C:D2C I2?8
36B36523652 .?DE =63:9 6292: @?C6A :?: A6B92D:2? 2'6
36B:ED :?:
I(W/m2)
2'6 6?E?;E2? CA6DBE B25:2C: '2D292B: I2?8 5:EEB
5: =E2B 2?82C2 !B27: D6BC63ED C2?82D :B:A 56?82? 8B27: :?D6?C:D2C
B25:2C: 36?52 9:D2 )=69 2B6?2 :DE A2B2 2CDB@?@ 6?82CEC:2?
'2D292B: C63282: 36?52 9:D2 C69:?882 3:C2 5:9:DE?8 36B2A2 CE9E 5:
A6BE22? '2D292B: 56?82? 6?88E?22? EE *6B86C6B2? 0:6?
2B: 8B27: D6B=:92D 329G2 ?:=2: :?D6?C:D2C 2C:E D6B52A2D A252
A2?;2?8 86=@32?8 C636C2B K 526B29 A2?;2?8 86=@32?8 C:?2B
D2A2 '6?EBED EE *6B86C6B2?0:6? 22? 5:52A2D2? ?:=2: CE9E
5: A6BE22? '2D292B: C63282: 36B:ED
Mari Mencari Tahu
Kata Kunci
• benda hitam
• radiasi benda hitam
• emisivitas benda
• intensitas
• daya radiasi
• spektrum
• energi radiasi
• radiasi termal
Ingatlah
182 Mudah dan Aktif Belajar Fisika untuk Kelas XII
2C
P

71. M%
P

72. %
P

73. %
,6=2:? E?DE 6?8EEB CE9E '2D292B: A6?6B2A2? B25:2C: 36?52
9:D2 :?: 52A2D 5:8E?22? E?DE 6?8EEB CE9E 3:?D2?8 =2:??I2 I2:DE
56?82? 6?82?2=:C:C CA6DBE 3:?D2?8 D6BC63ED
Gambar 7.8
Grafik intensitas radiasi
Matahari yang diukur di luar
angkasa.

76. 7 10 m
,2=29C2DE:CE8=@32=I2?8C6B:?85:2?82D@=692D:F:D2C=:?8E?82?9:5EA252=29
:CE D6?D2?8 A62?2C2? E: 52 C6328:2? ?682B2 2;E I2?8 D:52 2E
6?2?52D2?82?:+(-($(%1(-(D6?D2?8A632D2C2?252B6:C:82C52B::?5ECDB:
!2C6:C::?:C6328:2?36C2B252=29)
'6?EBEDA2B229=:82C)
:?:=29I2?8
6?82:32D2?A62?2C2?E:2D2E5:6?2=56?82?:CD:=29$.!
+'(.,- 2B:=29:?7@B2C:52B:36B3282:CE36B3EE2;2=29:?D6B?6D
52?=2:?=2:?D6?D2?89E3E?82?2?D2B2676BE2924252?B25:2C:36?529:D2
:CEC:2?=2956?82?D62?C66=2C?52D6?D2?892=:?:
1 Å = 10–10 m
Tantangan
untuk Anda
Grafik pada Gambar 7.8
menunjukkan intensitas radiasi
Matahari yang diukur di luar angkasa.
Apakah Anda bisa menduga
bagaimana grafik intensitas radiasi
Matahari jika diukur di permukaan
Bumi? Apakah di seluruh tempat di
permukaan Bumi intensitas radiasi
Matahari selalu sama? Jelaskan
jawaban Anda dengan bahasa yang
mudah dipahami dan diskusikanlah
bersama teman sekelas.

77. 3
Gambar 7.9
(a) Cahaya sebagai gelombang;
(b) Cahaya sebagai paket-paket
energi.
ruang vakum
tutup
tabung
cahaya
C
i
A
saklar geser
T
i
– + – +
V
Radiasi Benda Hitam 183

78. ,E9E6B;27:=26?DE?8CD6?52=2CE2DE=2AEA:;2B
252=29
%52?6:C:F:D2C?I2 -6?DE2?=E2C
A6BE22?7:=26?=2AEA:;2B0
,63E29=E32?864:=A2525:?5:?8-'.+6?I6BEA2:
36?529:D2 $:2=E2C?I2

79. 4
52?CE9E?I2

80. L
C22C6A6BD:CE9E5:52=2D2?EB36B2A2296?6B8:
I2?85:B25:2C:2?6=E2B=E32?8C6D:2A56D:
@=2+436BC:72DC6A6BD:36?529:D236B252
52=2 62522? C6:32?8 56?82? =:?8E?82??I2
-6B?I2D2 3@=2 6?I6B2A 52I2 0 52B:
=:?8E?82??I2 6B2A229CE9E3@=2:DE
2AEA:;2B52A2D5:2?882A36B36?DE3@=2 $2B:;2B:
=2AEA:;2BA6BD22252=295E22=:;2B:;2B:=2AE
65E2 ,E9EA:;2BA6BD2252?65E22C:?82C:?8
L52?
L -6?DE2??:=2:A6B32?5:?82?2?D2B2
52I22=@BB25:2C:=2AEA6BD2252?=2AE65E2
%@?CD2?D26:C:F:D2CC63E2936?529:D2252=29
:DE?8=29:?D6?C:D2CB25:2C:I2?85:A2?42B2?2A23:=2
CE9E36?52:DE

81. %
,63E293@=2=@8256?82?;2B:;2B:45:A2?2C2?
*252CE9E
L3@=2=@82:DE62?42B2?B25:2C:
56?82?52I2

82. P

83. G2DD :DE?8=296:C:F:D2C3@=2
=@82D6BC63ED
:DE?8=2952I2I2?85:A2?42B2?@=69C63E29E3EC
I2?85:A2?2C2?9:?882
L %E3ECD6BC63ED6:=::
A2?;2?8 C:C: 4 52? D6B3E2D 52B: 3292? 56?82?
6:C:F:D2C
6?5262?42B2?B25:2C:56?82?2H?
6?52 :DE D6BEC 6?82=2: A62?2C2? C69:?882
CE9E?I22=:=:A2DCE9EC6E=2 -6?DE2?=29 2H
C6D6=29A62?2C2?
Tes Kompetensi Subbab A
*6/031-5)'90918.-3
B. Dualisme Gelombang Partikel
1. Sifat Partikel yang Dimiliki Gelombang
*252 E=2?I2 32?I2 7:C:2G2? I2?8 6?82?882A 4292I2 C63282:
86=@32?8 2= :?: 5:A6BE2D 56?82? 252?I2 5:7B2C: A@=2B:C2C: B67B2C:
B67=6C:52?:?D6B76B6?C:I2?8C6CE2:56?82?C:72DEE86=@32?8 2?
D6D2A: 6D:2 A2B2 7:C:2G2? 6?6E2? 76?@6?2 B25:2C: 36?52 9:D2
6767@D@=:CDB:52?676@AD@?2CEC:4292I2C63282:86=@32?8D:52
52A2D 6?;6=2C2? 76?@6?276?@6?2 D6BC63ED %6E5:2? E?4E==29
A2?52?82? 329G2 4292I2 252=29 A2BD:6= ,63282: 2?2=@8: A6B92D:29
2'6 *252 8232B D6BC63ED ?52 3:C2 66B92D:2? A6B36522?
4292I2;:25:2CEC:2?C63282:86=@32?852?C63282:A2BD:6= 6?82?
2CEC: C63282: 86=@32?8 4292I2 5:A2?42B2? C63282: B232D2?
86=@32?8I2?8@?D:?E 52AE?56?82?2CEC:C63282:A2BD:6=4292I2
5:A2?42B2? 52=2 36?DE A26DA26D 6?6B8: I2?8 5:C63ED 7@D@?
,EA2I2?52=63:96292:2CEC:4292I2C63282:A2BD:6=?52
3:C2 6A6=2;2B: 676 7@D@=:CDB: 52? 676 @AD@? 36B:ED
a. Efek Fotolistrik
#% -+%),'1 %$-+('%$-+(' + )+.$' )%- %( $-$
,'+' '+$.',-+-'-.,.-$(-(%,-+$ =6DB@?I2?8D6B=6A2C
52B: A6BE22? A=2D =@82 D6BC63ED 5:C63ED 6=6DB@? 7@D@ *6B:CD:G2 :?:
A6BD222=:5:D6E2?@=69*68C6A6BD:5:8232B2?A2522'6
*6B2?82D A6B4@322? E?DE 6?822D: 676 7@D@=:CDB: D6B5:B: 2D2C
D23E?8 242 92A2 E52B2 52? A=2D =@82 I2?8 5:C63ED C63282: 2D@56
%6D:2 2D@56 5:C:?2B: 56?82? C:?2B E=DB2F:@=6D 6=6DB@? 22? D6B=6A2C
52B: 2D@56 52? 36B86B2 6?E;E 2?@56 C69:?882 2BEC 6?82=:B A252
B2?82:2? 2?I2?I26=6DB@?I2?8D6B=6A2C52A2DD6B=:92D52B::?5:2D@B
E2D2BECI2?85:DE?;E2?@=692A6B66D6B ?6B8::?6D:I2?85::=::
6=6DB@? 52A2D 5:D6?DE2? 56?82? 42B2 6A6B36C2B 3652 A@D6?C:2=
2?D2B2 2D@56 52? 2?@56 C69:?882 3652 A@D6?C:2= 36BC:72D 6?292? =2;E
2
Gambar 7.10
Skema eksperimen efek fotolistrik.

84. I
intensitas
tinggi
intensitas
rendah
2
–V0 V
3
f0 f0 f0
energi potensial
gelombang (eV)
0 2 4 6 8
Ce
Na
K
1014 Hz
Gambar 7.11
Ek
v
4
(a) Apabila energi kinetik elektron
melebihi energi potensial
penghalang, elektron akan dapat
mendaki bukit potensial; (b) Energi
kinetik elektron tidak bergantung
pada intensitas cahaya; (c) Setiap
permukaan memiliki frekuensi (f0)
berbeda.
6=6DB@? 6BC222? 56?82? 6?2:2? 3652 A@D6?C:2= A6?E?;E2? ;2BE
2A6B66D6B 22? 6?864:= $:2 A252 CE2DE 6D:2 ;2BE 2A6B6D6B
6?E?;E2?82?@=36C2B?I26?6B8:A@D6?C:2=C2256?82?36C2B6?6B8:
:?6D: I2?8 5::=:: 6=6DB@? (:=2: 3652 A@D6?C:2= A252 C22D :DE 5:C63ED
A@D6?C:2= 96?D:
?6B8:A@D6?C:2= I2?85:36B:2?52A2D5:AB65:C:2?C63282:C63E29
3E:DI2?892BEC5:=6G2D:6=6DB@?C6A6BD:A2522'6 A23:=2
3E:D A@D6?C:2= D6BEC 5:A6BD:?88: CE2DE C22D 2A6B66D6B I2?8 5:A2C2?8
5:32=:3E:D6?E?;E2?2?82?@= #?:36B2BD:6?6B8::?6D:6=6DB@?
D:52 4EEA =28: E?DE 6=6G2D: 3E:D A@D6?C:2= C69:?882 36C2B?I2
A@D6?C:2= 96?D: 36BC6CE2:2? 56?82? 6?6B8: :?6D: 6=6DB@?
3
2
1
184 Mudah dan Aktif Belajar Fisika untuk Kelas XII
$
M
2D2E

85. /
2C
M
CA6B:6? I2?8 5:=2E2? @=69 .378*.3 56?82? 6?8E329E329
7B6E6?C: 4292I2 I2?8 ;2DE9 A252 A=2D =@82 2D@56 :?D6?C:D2C 4292I2
52? A@D6?C:2= A6?892=2?8 A252 676 7@D@=:CDB: 636B:2? 3636B2A2
6C:AE=2? C63282: 36B:ED
2 6C2B6?6B8::?6D:2C:E6=6DB@?D:5236B82?DE?8A252:?D6?C:D2C
4292I2A6B92D:2?2'6 '
3 ,6D:2AA6BE22?=@8263EDE92?7B6E6?C::?:ED6BD6?DEI2?8
5:C63ED 7B6E6?C: 232?8 282B 676 7@D@=:CDB: 52A2D 36B=2?8CE?8
A6B92D:2? 2'6 (
4 =6DB@?6=6DB@?5:3632C2?52B:A6BE22?=@8292A:BD2?A2C6=2?8
G2DEI2:DEEB2?852B:

86. MC6@?C6D6=29A6?I:?2B2?
5 -6@B: 86=@32?8 D:52 52A2D 6?;6=2C2? 6?82A2 6?6B8: :?6D:
2C:E 6=6DB@? 36BD2329 ;:2 7B6E6?C: 4292I2 5:A6B36C2B
2C:= 6CA6B:6? D6BC63ED D:52 52A2D 5:;6=2C2? @=69 D6@B: =2C:
D6?D2?8 86=@32?8 6=6DB@28?6D: '6?EBED D6@B: =2C: 6?6B8: I2?8
5:2?5E?8 86=@32?8 6=6DB@28?6D: 36BC6CE2:2? 56?82? :?D6?C:D2C?I2
A23:=2 :?D6?C:D2C C62:? D:?88: 6?6B8: 86=@32?8 6=6DB@28?6D:
22? 6?:?88: AE=2 '652? =:CDB: I2?8 5:32G2 86=@32?8 6=6DB@
28?6D: 22? 636B:2? 82I2 A252 6=6DB@? 5: A6BE22? =@82
C69:?882 6=6DB@? 6A6B@=69 6?6B8: 52B: 86=@32?8 $:2 6?6B8: I2?8
5::=:: 6=6DB@? 4EEA 36C2B 6=6DB@? 22? D6B=6A2C 52B: A6BE22?
=@82 6B52C2B2?92=:DEC692BEC?I26?6B8::?6D:6=6DB@?36B82?DE?8
A252 :?D6?C:D2C 4292I2
%6925:B2?7B6E6?C:232?8AE?D:5252A2D5:;6=2C2?56?82?D6@B:
=2C: CA6B:6?6?E?;E2?329G2C664:=2A2AE?:?D6?C:D2C4292I2
2A23:=2 7B6E6?C:?I2 =63:9 36C2B 52B:A252 7B6E6?C: 676 7@D@=:CDB:
22?D6B;25: '6?EBEDD6@B:=2C:C692BEC?I2I2?8252252=29:?D6?C:D2C
232?8 6?82? 636B82?DE?82? 6?6B8: 4292I2 A252 :?D6?C:D2C?I2
9E3E?82? =:?62B 2?D2B2 6?6B8: :?6D: 6=6DB@? 52? 7B6E6?C: 86=@32?8
6=6DB@28?6D: C22 C62=: D:52 52A2D 5:;6=2C2?
'6?EBED 1'*68 .378*.3 C6E2 6?6B8: 7@D@? 5:36B:2? 6A252
6=6DB@? 52? :?: 6?I63232? 7@D@? =6?I2A #2 36BA2?52?82? 329G2
E2?DE 6BEA22? C:72D 86=@32?8 :DE C6?5:B: '6?EBED?I2 4292I2
Sumber: Fisika untuk Sains dan Teknik Tipler

87. Ingatlah
Informasi
untuk Anda
Information for You
Radiasi Benda Hitam 185
D6B5:B:2D2CA26DA26DI2?85:C63EDC63282:7@D@? @D@?7@D@?6BEA22?
A2BD:6=I2?8D:5236B2CC2I2?85:C6B2A52?5:A2?42B2? ?6B8:I2?85::=::
@=697@D@?C2256?82?E2?D2I2?85:6E22?@=69*=2?4I2:DE
!
56?82? ! 252=29 @?CD2?D2 *=2?4 52? 252=29 7B6E6?C: 86=@32?8
6=6DB@28?6D:
:?CD6:? 52A2D 6?;6=2C2? C642B2 C6AEB?2 92C:= 676 7@D@=:CDB:
292I2 I2?8 ;2DE9 5: 2D2C =@82 5:=E:C2? C63282: B6?D6D2? 7@D@? I2?8
6?E3E A252 =@82 C6D:2A 7@D@? 6?E3E 6=6DB@? 52=2 =@82
*252 A6B:CD:G2 DE3E2? D6BC63ED 7@D@? 636B:2? C6=EBE9 6?6B8:?I2
6A252 6=6DB@? 52? 7@D@? :DE C6?5:B: 6?;25: =6?I2A
?6B8:I2?85:A6B=E2?E?DE6=6A2C2?5:B:52B:A6BE22?=@82
5:C63ED7E?8C:6B;2 .?DE;6?:C=@82I2?836B3652D6?DE?I27E?8C:
6B;2 22? 36B3652 AE=2 2B6?2 A6B36522? 6?6B8: :2D 2?D2B2 6=6DB@?
52? :@? 52=2 =@82 $25: E?DE =@82 D6BD6?DE 36B=2E
! M
$:27B6E6?C:7@D@?=63:936C2B52B:A2527B6E6?C:232?86=63:92?
6?6B8: I2?8 5:D6B:2 6=6DB@? :DE 22? 6?;25: 6?6B8: :?6D: 6=6DB@?
!2!
$ M

88. !
!$
!
$ M

90. Keterangan:
! @?CD2?D2*=2?4P

91. M$C
7B6E6?C: 86=@32?8 4292I2 J
7B6E6?C: 232?8 J
$:25:3E2D52=2C63E29D236=7E?8C:6B;27@D@=:CDB:3636B2A2;6?:C
=@82 3:C2 5:=:92D 52=2 '*1
1 eV = 1,6 × 10–19 J
'*1
E?8C:%6B;2=6DB@?A252636B2A2@82
4,2 2'3, 93,7.*6/%*$
6C:E C

92. %2=:E %
(2DB:E (2
2C E

93. -63282 E
*6B2 8
*=2D:?2 *D
Efek fotolistrik selain memiliki
peranan penting dalam teori foton
pada cahaya, juga memiliki banyak
sekali aplikasi dalam kehidupan
sehari-hari. Sebagai contoh adalah
alarm pencuri dan pembuka
otomatis yang juga menggunakan
sirkuit fotolistrik. Ketika seseorang
menghalangi sinar yang dipancarkan,
penurunan arus listrik dapat
mengaktifkan saklar sehingga bel
berbunyi atau pintu terbuka.
Biasanya sinar yang digunakan adalah
sinar ultraviolet dan inframerah
karena kedua sinar ini tidak terlihat.
The photoelectric effect, besides
playing an important historical role
in confirming the photon theory of
light, also has many practical
applications. Burglar alarms and
automatic door openers often make
use of the photocell circuit. When a
person interrupts the beam of light, the
sudden drop in current in the circuit
activates a switch which operates a
bell or opens the door. UV or IR light is
sometimes used in burglar alarms
because of its invisibility.
Sumber: Physics for Scientist Engineers
Contoh 7.6
Sumber: Physics, 1993
B6E6?C:232?8CE2DE3292?

94. P

96. J $:23292?D6BC63ED5:C:?2B:56?82?C:?2B
I2?86:=::7B6E6?C:
P

98. JD6?DE2?36C2B6?6B8::?6D:6=6DB@?I2?8
D6B=6A2C52B:A6BE22?=@82D6BC63ED
;'
$!2!!2
$P

99. M$C
P

101. JM

102. P

104. J
$P

105. M$CP

107. J

108. P

109. M

110. ;@E=6

111. Contoh 7.7
%2=:E5:C:?2B:56?82?4292I2E=DB2F:@=6DI2?8A2?;2?886=@32?8?I2
K $:27E?8C:
6B;22=:E

112. 6/D6?DE2?=29?:=2:A@D6?C:2=96?D:A252A6B:CD:G26767@D@=:CDB:
D6BC63ED!P

113. M$C
;'
:6D29E:
K
P

114. M

115. 6/

116. 6/

117. P

118. M

119. $C
P

120. M

121. $
?6B8::?6D:2C:E6=6DB@?$
!2
!

122. $C

123. C

124. $
Ingatlah
186 Mudah dan Aktif Belajar Fisika untuk Kelas XII
2
$

125. $P

126. M

127. $
%6E5:2?8E?22?*6723?C69:?882
$ 2D2E $

128. $

129. /
$25:A@D6?C:2=96?D:A2526767@D@=:CDB:D6BC63ED252=29
/
b. Efek Compton
2=2A6B:CD:G26767@D@=:CDB:4292I2I2?85:;2DE92?A2526A:?8
=@82 5:A6B=2E2? C63282: A26D 6?6B8: I2?8 5:C63ED 7@D@? @D@? :DE
6?82=2: A6B:CD:G2 DE3E2? 56?82? 6=6DB@? :2C2?I2 DE3E2?
C6=2=E 5:9E3E?82? 56?82? @6?DE *252 A6B:CD:G2 D6BC63ED 22?
36B=2E EE %662=2? '@6?DE 52? EE %662=2? ?6B8:
*6?6=:D:2? 923EB2? C:?2B1 I2?8 5:=2E2? 68-96 425843

130. M

131. 6?892C:=2? 76?@6?2 32BE I2:DE A6B86C6B2? A2?;2?8
86=@32?8 2D2E A6BE3292? 7B6E6?C: C636=E 52? C6CE529 DE3E2?
!6;2=2 :?: 5:;6=2C2? @=69 425843 56?82? 6?82?882A 329G2 I2?8
D6B;25: 252=29 DE3E2? 2?D2B2 E2?DE 4292I2 7@D@? 52? 6=6DB@?
3632C %6D:2 7@D@? 6?E3E 6=6DB@? C6328:2? 6?6B8: 7@D@? 22?
5:36B:2? 6A252 6=6DB@? C69:?882 6=6DB@? 6:=:: 6?6B8: :?6D:
52AE? 6?6B8: 7@D@? C6D6=29 DE3E2? 22? 36BEB2?8 '6?EBED D6@B:
=2C: A6?8EB2?82? 6?6B8: D:52 22? 5::ED: @=69 A6BE3292? 7B6E6?C:
2D2E A2?;2?8 86=@32?8 (2E? 6?EBED D6@B: E2?DE A6BE3292?
6?6B8: 36B2BD: 22? D6B;25: A6BE3292? 7B6E6?C: 52? A6BE3292? A2?;2?8
86=@32?8 #?: 5:3ED:2? 52B: 92C:= A6?822D2? I2?8 6?E?;E2?
329G2 C6D6=29 DE3E2? A2?;2?8 86=@32?8 7@D@? 36BD2329 36C2B
)=69 2B6?2 6?6B8: 7@D@? 5:BEEC2? C63282: !
;6=2C=29
329G2 6?6B8: 7@D@? C6D6=29 DE3E2? 22? 36BEB2?8
42*3892 +4843
%6C6D2B22?2CC252?6?6B8:6?EBED.378*.3252=29
2=
D6BC63ED22??52A6=2;2B:52=2A@@3292C2?36B:ED?I2C652?82?
Foton merupakan paket-paket
energi pada cahaya. Konsep ini
merupakan kelanjutan dari asumsi
cahaya merupakan partikel.
Tugas Anda 7.2
Proses terjadinya sinar-X
merupakan kebalikan dari proses
fotolistrik. Carilah informasi dari
berbagai sumber tentang sinar-X
dan diskusikanlah bersama teman
sekelas Anda.
)=692B6?2

132. ;@E=6

133. P

134. M

135. 6/36C2B6?6B8::?6D:6=6DB@?I2?8D6B=6A2C
252=29

138. $
6/
6/

139. foton dengan , p
2
3
foton terhambur
', p'
elektron
terdorong
pe
Radiasi Benda Hitam 187
6?EBED *=2?4 4292I2 36B36?DE A26DA26D 6?6B8: 56?82? 6?6B8:
7@D@? C636C2B
! 6?82? 56::2? A6?562D2? C642B2 B6=2D:F:CD:
52A2D 5:DE=:C
!
M

140. !
2B:*6723? ?5252A2D6A6B@=69A6BC222?@6?DE
B6=2D:F:CD: 52B: C63E29 7@D@? I2:DE
!
M

141. )
52?

142. :6D29E:
22 *6723 ?
52A2D 5:DE=:C
) ! 2D2E !
M

143. )
%6D6B2?82?
) @6?DEC63E297@D@?8
C
46A2D B232D 4292I2
C
A2?;2?8 86=@32?8 4292I2
! D6D2A2?*=2?4P

144. M$C
7B6E6?C: 4292I2 J
*69'-3 3/3, *142'3, 5) 2'963 425843
*6B92D:2?DE3E2?2?D2B2C63E297@D@?52?C63E296=6DB@?C6A6BD:
5:DE?;E2? A252 2'6 ,636=E DE3E2? 7@D@? 6:=::
A2?;2?886=@32?8 52?6=6DB@?36B25252=262522?5:2 ,6D6=29
DE3E2? 7@D@? D6B923EB 56?82? CE5ED 52? 6?82=2: A6?EBE?2?
6?6B8: 6?;25: : =2:? A:92 C6328:2? 6=6DB@? 636?DE CE5ED
56?82? 2B29 86B2 7@D@? C636=E DE3E2? 23EB2? I2?8 5:2=2:
@=69 7@D@? 5:C63ED 923EB2? @AD@? 56?82? 4:B:4:B: 92C?I2 D6B;25:
A6BE3292? 52?A6BE3292? .?DE6?86D29E:A6BE3292?6?6B8:2D2E
A2?;2?8 86=@32?8 7@D@? C6D6=29 D6B923EB 5:8E?22? 2?2=:C:C 56?82?
EE %662=2? '@6?DE 52? EE %662=2? ?6B8: )=69
2B6?2 6?6B8: I2?8 D6B=:32D C2?82D D:?88: C6BD2 6E?8:?2? 36C2B
646A2D2? 6=6DB@? C6D6=29 DE3E2? C2?82D 36C2B A6BC222? 5:?2:2
I2?8 5:8E?22? 252=29 5:?2:2 B6=2D:F:CD:
6?82? 6?88E?22? EE %662=2? ?6B8: 52? EE
%662=2? '@6?DE 52=2 5:?2:2 +6=2D:F:CD: 5:52A2D2?
A6BC222? 923EB2? @AD@? C63282: 36B:ED
!

145. 4@C
M

146. Keterangan:
A2?;2?8 86=@32?8 7@D@? C636=E DE3E2?
’ A2?;2?8 86=@32?8 7@D@? C6CE529 DE3E2?
! D6D2A2?*=2?4P

147. M$C
46A2DB232D4292I2P

148. C
CE5ED A6?I:A2?82? 7@D@?
2CC2 5:2 6=6DB@? 8
Gambar 7.12
Tumbukan foton dan elektron
(a) sebelum tumbukan
(b) sesudah tumbukan
v
Tokoh
Arthur Compton (Holly)
(1892–1962)
Arthur Compton adalah seorang ahli
Fisika yang dilahirkan di Wooster,
Ohio, USA. Dia belajar di Universitas
Princetion dan lulus menjadi
profesor Fisika di Chicago (1923). Dia
meneliti dan menjelaskan Efek
Compton, penambahan panjang
gelombang sinar-X yang
dihamburkan ketika bertumbukan
dengan elektron. Untuk sumbangan
pemikirannya tersebut, dia
mendapat penghargaan Nobel Fisika
pada 1927.
Sumber: www.allbiographies.com
elektron diam

149. Ek (eV)
f (Hz)
0,2
3,7
f0
*252 *6723 ?

150. CEE
!
5:C63ED ;E82 A2?;2?8 86=@32?8
@AD@? ?:=2:?I2 252=29
!
,:?2B156?82?A2?;2?886=@32?8
?5:923EB2?@=69C63E2932=@2B3@?
,:?2B1I2?85:923EB2?5:22D:6?I:A2?8LD6B9252A2B29?I2C6E=2 :DE?8
A2?;2?886=@32?8C:?2B1I2?85:923EB2?:?:
;'
652A2?;2?886=@32?87@D@?C636=E52?C6CE5295:923EB2?52A2D5:9:DE?856?82?
*6723?
!

151. 4@C
:6D29E:
?!P

152. M$C52?

153. P

154. M

155. 8
22

156. $C
19
0,2 3,7 1,6 10 J
34
188 Mudah dan Aktif Belajar Fisika untuk Kelas XII

157. 4@C

159. 8

160. C

162. P

163. M

165. ?
*2?;2?886=@32?87@D@?C:?2B1I2?85:923EB2?252=29
’
?

167. ?

169. ?
2. Sifat Gelombang pada Partikel
*252 A63292C2? C636=E?I2 D6=29 5:;6=2C2? 329G2 86=@32?8
6:=:: C:72D A2BD:6= ,62B2?8 E?4E= A6BD2?I22? 2A229 A2BD:6=
6:=:: C:72D 86=@32?8 2=2 A6B:CD:G2 :?D6B76B6?C: 52? 5:7B2C:
4292I2 C:72D 86=@32?8 4292I2 =63:9 6?@?;@= 52B:A252 C:72D A2BD:6=
4292I2 52AE? 52=2 A6B:CD:G2 676 7@D@=:CDB: 52? 676 @AD@? C:72D
A2BD:6= 4292I2 =63:9 6?@?;@= 52B:A252 C:72D 86=@32?8 4292I2
*252

170. :C:2G2?36B632?8C22?*B2?4:C49.7)*64,1.*252=29
@B2?8A6BD22I2?86?82;E2?9:A@D6C:C329G2A2BD:6=C6A6BD:6=6DB@?
;E82 52A2D 36BC:72D C63282: 86=@32?8
a. Panjang Gelombang de Broglie
49.7 )* 64,1.* 6?I2D22? 329G2 6=6DB@? I2?8 36B86B2 252
6E?8:?2? 6:=:: C:72D 86=@32?8 56?82? A2?;2?8 86=@32?8 I2?8
C6CE2: *2BD:6= I2?8 36B86B2 56?82? 646A2D2? / 6:=:: @6?DE
)
/ 2D2E C642B2 B6=2D:F:CD: 5:DE=:C2? C63282: 36B:ED
!
)
)=692B6?2
22
! )
!
C69:?882 A2?;2?8 86=@32?8 56 B@8=:6 252=29
! !
) /
M

171. $C

173. 8

174. C
Contoh 7.8
Pembahasan Soal
Grafik di atas menunjukkan
hubungan antara energi kinetik
maksimum elektron terhadap
frekuensi foton pada efek
fotolistrik. Jika h = 6,6 × 10–34 Js dan
1 eV = 1,6 × 10–19 J, besar f adalah ....
a. 48 × 1014 Hz
b. 21 × 1014 Hz
c. 14 × 1014 Hz
d. 9,5 × 1014 Hz
e. 8,9 × 1014 Hz
UMPTN 1996
Pembahasan
Menurut persamaan efek fotolistrik
Ek = hf – W
maka
f =
k E W
h
Dari grafik, nilai Ek = 0,2 eV = 0,2 (1,6 ×
10–19) J
Pada saat f = 0, berlaku
Ek = – W atau W = –Ek
Dari grafik, saat f = 0, nilai Ek = –37 eV,
maka W = 3,7 eV = 3,7 (1,6 × 10–19) J
Jadi,
f = Ek W
h =
6,6 10 Js
= 9,5 × 1014 Hz
Jawaban: d

175. Sumber: Conceptual of Physics, 2000
Radiasi Benda Hitam 189
%6D6B2?82?
A2?;2?8 86=@32?8 A2BD:6= 6?EBED 56 B@8=:6
! D6D2A2?*=2?4P

176. M$C
2CC2 5:2 A2BD:6= 8
/ =2;E A2BD:6=
C
2=2 A6?822D2??I2 )* 64,1.* 6=:92D 329G2 36B2C 6=6DB@?
5:923EB2? @=69 2D@2D@ A6BE22? ?:6= D6A2D C6A6BD: I2?8
5:A6B:B22?E?DE5:7B2C:86=@32?86?EBEDBEECB28852?6:=::
A2?;2?8 86=@32?8 I2?8 C6CE2: 56?82? I2?8 5:36B:2? @=69 A6BC222?
56 B@8=:6 2C:= A6B4@322? :?: 6I2:?2? )* 64,1.* 329G2 A2BD:6=
6=6DB@? I2?8 36B86B2 52A2D 6:=:: C:72D 86=@32?8 I2?8 5:4:B:2?
@=69 A2?;2?8 86=@32?8?I2

177. $C

178. $C
Contoh 7.10
,63E296=6DB@?I2?8E=2E=25:25:A6B46A2D@=693652A@D6?C:2==:CDB:
$:22CC26=6DB@?E2D2?6=6DB@?52?D6D2A2?*=2?4!D6?DE2?=29A2?;2?8
86=@32?86=6DB@?D6BC63ED $:25::?8:?2?A2?;2?886=@32?8 K
36B2A236C2BI2?892BEC5:36B:2?

179. P

180. M

181. 8

182. P

183. M

184. 52?
!P

185. M$C
;'
,63E296=6DB@?I2?85:A6B46A2D56?82?3652A@D6?C:2=52B:62522?5:222?
6?6B:2)=:CDB:52?6?8E329?I26?;25:$6=6DB@?

186. /
C69:?88236B=2E

187. / 2D2E
/
*2?;2?886=@32?856B@8=:66=6DB@?252=29
! ! ! !
/
82B KP

188. M

189. 2252A2D5:9:DE?8C63282:36B:ED

190. $C

193. 8

194. /
P

195. M

196. P

197. M

198. 8

199. P

200. M

201. P

202. M$C

204. F@=D
Tokoh
Louis Victor de Broglie
(1892–1987)
Louis Victor De Broglie (1892–
1987) lahir di Dieppe, Prancis, dan
bersekolah di Sorbonne. Ia
melanjutkan kuliahnya di Universitas
Paris tahun 1926. Pada 1929, ia
menerima hadiah Nobel dalam
bidang Fisika atas teorinya mengenai
sifat gelombang pada partikel. Teori
ini menjadi dasar dari mekanika
kuantum, cabang dari ilmu Fisika.
Pada awal 1800, para fisikawan
percaya bahwa cahaya terdiri atas
gelombang energi. Pada 1900, Max
Planck menunjukkan bahwa cahaya
dapat bersifat partikel. Pada 1924, de
Broglie menyatakan bahwa elektron
dapat bersifat sebagai partikel dan
gelombang.
Tantangan
untuk Anda
Efek Compton diaplikasikan dalam
dunia kedokteran untuk mendeteksi
kepadatan tulang. Dengan bahasa
Anda sendiri, dapatkah Anda
menjelaskan cara kerjanya?
Contoh 7.9
-6?DE2?A2?;2?886=@32?856B@8=:6E?DE36?5236B:ED:?:
2 @=256?82?2CC28I2?836B86B256?82?646A2D2?
C
3 =6DB@?I2?836B86B256?82?6?6B8::?6D:

205. 6/
;'
:6D29E:8/
C
2

206. 8
C
!
/
3 $=6/

207. P

208. M

209. $

211. 8

213. $ $ )

215. 8
C

216. 8
C
!
)

217. b. Eksperimen Davisson-Germer
*252

218. :.7743 52? *62*6 6=2E2? A6?6=:D:2?
6?86?2:923EB2?6=6DB@? '6B626?;2DE92?36B2C6=6DB@?I2?8
6:=:: 6?6B8: :?6D: D6BD6?DE 6 2D2C B:CD2= DE?882= ?:6= '6B62
6?822D: 329G2 A252 CE5ED D6BD6?DE D6B;25: D:D: 2C:E I2?8
36B9E3E?82? 56?82? A@=2 :?D6B76B6?C: 6B52C2B2? 52D2 I2?8 5:A6B@=69
A2?;2?8 86=@32?8 I2?8 5:52A2D2? D6B?I2D2 252 6C6CE2:2? 2?D2B2
92C:= I2?8 6B62 A6B@=69 52? A2?;2?8 86=@32?8 I2?8 5:52A2D2?
6?EBED 9:A@D6C:C 56 B@8=:6 ,62 2=2D A6B4@322? I2?8 5:=2E2?
6B62 D2A2 A252 2'6
=6DB@?I2?85:8E?22?52B:2G2D7:=26?A252D23E?892A2E52B2
5:=6G2D2?6=2=E:652?=:CDB:56?82?A@D6?C:2=I2?852A2D5:2DEB ,6D6=29
5:9:DE?8 A2?;2?8 86=@32?8 I2?8 5::=:: @=69 6=6DB@? @B56?I2 C22
36C2B 56?82? ;2B2 2D@2D@ 52=2 B:CD2= 3292? A252D 6?82?
6?822D:CE5EDCE5EDA2?DE=6=6DB@?C6D6=296?86?2:B:CD2=:.7743
52?*62*66A6B@=69A@=2A@=25:7B2C:C6A6BD:A2522'6I2?8
C22 56?82? A@=2 5:7B2C: @=69 C:?2B1 2C:= 6CA6B:6? :.7743 52?
*62*66?E?;E2?329G2A2BD:6=C6A6BD:6=6DB@?52A2D36BC:72DC63282:
86=@32?8
*2526CA6B:6?:.7743*62*636B2C6=6DB@?I2?8;2DE9A252
3:52?8 A62?DE= B:CD2= 56?82? CE5ED 52? 3:52?8 A62?DE= I2?8
6:=:: C6=2?8 ;2B2 C636C2B 22? 6?8923EB2? 6=6DB@? 56?82?
CE5ED923EB E3E?82?;2B22?D2B22D@52?;2B22?D2B23:52?8
A62?DE= 66?E9: A6BC222? 36B:ED
detektor
sinar datang
190 Mudah dan Aktif Belajar Fisika untuk Kelas XII
4@C
M

219. 2B: 2'6 D6B=:92D 329G2 52? 66?E9: 9E3E?82?
C69:?882 *6BC222? M

220. 36BE329 6?;25:
C:? M

221. %6D:2 6=6DB@? 5:A6B46A2D 56?82? 3652 A@D6?C:2= F@=D
:?D6B76B6?C:2C:E22?D6B;25:A252 L 6?82?6?88E?22?
*6723??:=2: 22?5:A6B@=69E?DE;2B22?D2B22D@?:6=

222. ? $:2 5:32?5:?82? 56?82? ?:=2: I2?8 5:A6B@=69
36B52C2B2?D6@B:)*64,1.*22?6?892C:=2??:=2:A2?;2?886=@32?8
I2?8 C22
6?82? 56::2? A6B9:DE?82? A2?;2?8 86=@32?8 I2?8 5:=2E2?
@=69 :.7743 *62*6 6?EBED A6B4@322? C22 56?82? A2?;2?8
86=@32?8 36B52C2B2? D6@B: )* 64,1.* :.7743*62*6 36B92C:=
6?E?;E2? 329G2 2D6B: 6:=:: C:72D 86=@32?8 *6B4@322?
A6B4@322? E?DE 63ED:2? 636B2522? A2BD:6= D6BEC 36B632?8
,2=29C2DE4@?D@9?I2252=29A@=2A@=25:7B2C:I2?8D6B;25:C63282:2:32D
36B2C 6=6DB@? I2?8 5:;2DE92? A252 B:CD2= 2=E:?:E *6?6E2? C:72D
86=@32?8A2BD:6=C6=2?;ED?I26=29:B2?CE2DE2;:2?32BE52=27:C:2
I2?8 5:C63ED 62?:2 86=@32?8
*252 2C2 C62B2?8 C:72D 86=@32?8 I2?8 5::=:: A2BD:6= D6=29
32?I2 5:2?722D2? ,:72DC:72D 3292? 5:C6=:5:: 56?82? 6=:92D A@=2
5:7B2C:6=6DB@?I2?85:;2DE92?A2523292?D6BC63ED ':B@C@A6=6DB@?
berkas
elektron
kristal
nikel
filamen
Gambar 7.13
Skema alat percobaan Davisson-
Germer. Berkas elektron
dijatuhkan pada kristal tunggal
nikel. Interferensi yang terjadi
pada sudut diamati pada detektor.
Gambar 7.14
Gambaran mengenai
hamburan elektron oleh
bidang kristal.
a
d
d
a
d
a
2
2
2

223. Kata Kunci
• gelombang partikel
• efek fotolistrik
• foton
• fungsi kerja
• efek Compton
• panjang gelombang de Broglie
• jarak antara bidang
• prinsip ketidakpastian
Heisenberg
Radiasi Benda Hitam 191
I2?8 5:8E?22? @=69 A2B2 29=: 3:@=@8: E?DE 6?6=:D: ;2C25 :B@C@A:C
6BEA22? 4@?D@9 A62?722D2? C:72D 86=@32?8 A2BD:6= ':B@C@A
6=6DB@? 52A2D 6?892C:=2? A6B36C2B2? I2?8 C2?82D D:?88:
c. Prinsip Ketidakpastian Heisenberg
A229 ?52 A6B?29 632I2?82? 3282:2?2 42B2 I2?8
5:8E?22?A2B27:C:2G2?E?DE6?822D:6=6DB@??52D6=2936=2;2B
D6?D2?86767@D@=:CDB:52?676@AD@?A2522D6B:C636=E?I2 *252
A63292C2?D6BC63EDD6B;25:DE3E2?2?D2B27@D@?52?6=6DB@? *6B:CD:G2
:?:=29 I2?8 5:8E?22? @=69 A2B2 7:C:2G2? E?DE 6?822D: 6=6DB@?
@D@? 5:D6322? 6 2B29 6=6DB@? C69:?882 D6B;25: DE3E2? 2?D2B2
65E2?I2 6E5:2? 7@D@? I2?8 D6BA2?DE=2? @=69 6=6DB@? :?: 5:22D:
@=69 A6?822D @D@? :?: 632G2 :?7@B2C: D6?D2?8 636B2522?
6=6DB@? 2? D6D2A: 636B2522? 6=6DB@? I2?8 5::?7@B2C:2? @=69
7@D@? D6BC63ED 3E2? 636B2522? 7@D@? I2?8 C636?2B?I2 6=2:?2?
636B2522? 6=6DB@? C6D6=29 DE3E2? 56?82? 7@D@? 6?82? 2D2 =2:?
2526D:52A2CD:2?A@C:C:6=6DB@?2:32DDE3E2?56?82?7@D@? *B:?C:A
:?: A6BD22 2=: 5:6E22? @=69 *.7*3'*6, 52? AB:?C:A :?: 5:6?2=
56?82? ?22 AB:?C:A 6D:52A2CD:2? 6:C6?36B8 .?DE =63:9 ;6=2C?I2
A6B92D:2? 8232B 36B:ED
foton datang
pengamat pengamat
elektron
bertumbukan
*252 A6B:CD:G2 D6BC63ED 7@D@? 6:=:: @6?DE C636C2B
! 52?
;:27@D@?36BDE3E2?56?82?6=6DB@?@6?DE2G2=6=6DB@?22?
36BE329 *6BE3292? I2?8 D6A2D D:52 3:C2 5:B22=2? D6D2A: A6BE3292?
:?: C632?5:?8 56?82? A6BE3292? @6?DE 7@D@?
! $25: A6?8EEB2?
D6BC63ED D6=29 6?I63232? 6D:52A2CD:2? C636C2B
) !
)=69 2B6?2 6D:52A2CD:2? A6?8EEB2? A@C:C: 6=6DB@? C6EB2?8
EB2?8?I2 C22 56?82? A2?;2?8 86=@32?8 I2?8 5:8E?22? I2:DE
0 %6D:52A2CD:2?@6?DE 52? A@C:C:?I2 252=29
)0 ! M

224. $25:5:52=2D6@B:+6=2D:F:CD:A@C:C:52?@6?DECE2DEA2BD:6=
D:5252A2D5:D6?DE2?D6A2DC642B236BC222? ,62:?36C2B6D6A2D2?
A@C:C: A2BD:6= C62:? 36C2B 6D:52A2CD:2? @6?DE?I2 ,632=:?I2
C62:? 36C2B 6D6A2D2? 92B82 @6?DE?I2 C62:? 64:= 6D6A2D2?
A@C:C:?I2 6B365256?82?D6@B:=2C:A@C:C:52?@6?DECE2DEA2BD:6=
52A2D 5:D6?DE2? C642B2 D6A2D 52? 36BC222?
Gambar 7.15
Tumbukan foton dan elektron
ketika mengamati elektron.
pengamat
momentum
elektron semula
momentum
elektron akhir
2 3 4
Sumber: Konsep Fisika Modern, 1983

226. @8246C:E6:=::7E?8C:6B;2

227. 6/
2 6B2A2A2?;2?84292I286=@32?8D6BA2?;2?8
I2?852A2D5:;2DE92?A252A6BE22?=@82
46C:E D2?A2 6?86=E2B2? 6=6DB@? 52B:
A6BE22?=@82
3 $:2 A6BE22? =@82 5:C:?2B: @=69 4292I2
@?@B@2D:56?82?A2?;2?886=@32?8?
9:DE?8=296?6B8::?6D:2C:E6=6DB@?7@D@
I2?86=E2B52B:A6BE22?=@82
4 6B2A229 A@D6?C:2= 96?D: I2?8 6?292?
6=E2B?I22BEC6=6DB@?
292I256?82?A2?;2?886=@32?8?6B25:2C:
A6BE22?=@82I2?86:=::7E?8C:6B;2P

228. M

229. ;@E=6 $:2 P

230. C 52? ! P

231. M $C
D6?DE2?
2 6?6B8::?6D:2C:E6=6DB@?7@D@?I2
3 A@D6?C:2=96?D:
,E2DE 36B2C C:?2B1 56?82? 6?6B8:

232. 6/
6?82=2: 923EB2? @AD@? 56?82? CE5ED L
-6?DE2?6?6B8:7@D@?C:?2B1C6CE529923EB2?
*6?E?DE?6?6B8:7@D@?5:BEEC2?@=69
!
,63E297@D@?6:=::A2?;2?886=@32?8?
6?82=2: 923EB2? @AD@? 56?82? CE5ED L
192 Mudah dan Aktif Belajar Fisika untuk Kelas XII
-6?DE2?=29
2 A2?;2?886=@32?8
3 6?6B8:7@D@?I2?85:923EB2?
4 6?6B8: I2?8 5:36B:2? 6A252 6=6DB@? I2?8
6=@A2D
,63E29A2BD:6=36B86B256?82?646A2D2?
P

233. C
6B2A229A2?;2?886=@32?8A2BD:6=;:2A2BD:6=
D6BC63ED
2 6=6DB@?
3 AB@D@?
4 3@=236B2CC28
6B2A229A2?;2?886=@32?87@D@?282B@6?DE
?I2C2256?82?@6?DE6=6DB@?I2?836B86B2
56?82?646A2D2?
P

234. C
,63ED2?=29 8282C2? I2?8 5:6E22? @=69 56
B@8=:6
:DE?8=29A2?;2?886=@32?856B@8=:6I2?85::=::
@=696=6DB@?I2?836B86B256?82?=2;EP

235. C
,63E29A2BD:6=36B2CC2

236. M86:=::A2?;2?8
86=@32?8 56 B@8=:6 C636C2B
? -6?DE2?=29
646A2D2?86B2A2BD:6=D6BC63ED

237. ,63E29A2BD:6=36B86B256?82?=2;E
P

238. C
:DE?8=29 2CC2 A2BD:6= D6BC63ED ;:2 A2?;2?8
86=@32?856B@8=:6I2?85::=::A2BD:6=:DE?
Tes Kompetensi Subbab B
*6/031-5)'90918.-3
Rangkuman

239. +25:2C:6=6DB@28?6D:I2?85:A2?42B2?@=6936?52
5:C63EDB25:2C:D6B2=
6?52 9:D2 252=29 CE2DE C:CD6 I2?8 52A2D
6?I6B2AC6E2B25:2C:2=@BI2?86?86?2:36?52
2D2EC:CD6D6BC63ED
'6?EBED,D672?@=DJ2??:?D6?C:D2CB25:2C:D6B2=
CE2DE36?525:?I2D22?56?82?
EE*6B86C6B2?0:6?6?I2D22?329G2A2?;2?8
86=@32?8 I2?8 CE9E?I2 D:?88: =63:9 A6?56
52B:A252A2?;2?886=@32?8:?D6?C:D2C36?52I2?8
CE9E?I2 B6?529 ,642B2 2D62D:C EE
*6B86C6B2?0:6?5:?I2D22?C63282:36B:ED
2C@?CD2?
-6@B:0:6? :?: 52A2D 6?6B2?82? CA6DBE A252
A2?;2?886=@32?8I2?8A6?56D6D2A:6?I:A2?8
6D:26?6B2?82?A2?;2?886=@32?8I2?8A2?;2?8
+2I=6:89$62?C 6A6B@=69 A6BEEC2? 329G2
:?D6?C:D2CB25:2C:36B32?5:?8D6B32=:56?82?A2?82D
6A2DA2?;2?886=@32?8
-6@B:+2I=6:89$62?C:?:52A2D6?6B2?82?CA6DBE
A252 A2?;2?8 86=@32?8 I2?8 A2?;2?8 D6D2A:
6?I:A2?8 6D:2 6?6B2?82? A2?;2?8
86=@32?8I2?8A6?56
'6?EBED-6@B:*=2?46?6B8:B25:2C:I2?85:A2?42B
2?@=6986D2B2?@=6E=36?526BEA22?A26D
E2?D26?6B8:I2?836C2B?I2
?'!
?6B8:E?DEC2DE7@D@?252=29C636C2B
!
767@D@=:CDB:252=2986;2=2D6B=6A2C?I26=6DB@?
6=6DB@?52B:A6BE22?A=2D=@826D:25:C:?2B:
56?82?7B6E6?C:D6BD6?DE *6BC222?I2?836B=2E
A25286;2=2:?:252=29
!
$
56?82?
!252=297E?8C:6B;26=6DB@?A252
=@82
E?8C:6B;2252=296?6B8::?:EI2?85:3EDE92?
6=6DB@?282BD6B=6A2C52B::2D2?:?D:2D@A252=@82
76 @AD@? 6?;6=2C2? 329G2 6D:2 7@D@?
6?E3E6=6DB@?7@D@?636B:2?6?6B8:A252
6=6DB@? %69:=2?82? 6?6B8: A252 7@D@? 5:D2?52:
56?82?6?864:=?I27B6E6?C:7@D@?2D2E36BD2329
A2?;2?8?I2A2?;2?886=@32?87@D@? '@6?DE
I2?85::=::7@D@?252=29
!
)
2D2E
) !

240. ) !
0 ! 2D2E)0 !
#?D6?C:D2C+25:2C: EE*6B86C6B2?0:6?
*B:?C:A 76 @D@=:CDB: 76@AD@?
Radiasi Benda Hitam 193

241. 6?82? 6?88E?22? EE %662=2? ?6B8:
52?EE%662=2?'@6?DE52=25:?2:2
B6=2D:F:CD: 5:52A2D2? A6BC222? 923EB2?
@AD@?C63282:36B:ED
! !
) /

243. ,:72D86=@32?8A252A2BD:6=A6BD222=:5:6?2=2?
@=69@E:C56B@8=:6 '6?EBED5:2A2?;2?886=@32?8
A2BD:6=A2?;2?886=@32?856B@8=:6252=29
C:?

244. *B:?C:A 6D:52A2CD:2? 6=6DB@? 6?88232B2?
329G2 :?7@B2C: D6?D2?8 6=6DB@? 636B2522??I2
D:52A2CD: 6C2B?I26D:52A2CD:2?C636C2B
)=69 2B6?2 6D:52A2CD:2? A6?8EEB2? 6=6DB@?
C6EB2?8EB2?8?I2C2256?82?A2?;2?886=@32?8
I2?8 5:8E?22? I2:DE 0 ! %6D:52A2CD:2?
@6?DE52?A@C:C:?I2252=29
Peta Konsep
).7.*3).82
A6?6B2A2??I2
D6B;25: A6?I:A2?82? E?DE
E?4E=
4@?D@9
A6?6B2A2?I2
63292C
*6BEEC2?+2I=6:89$62?C
D6B;25: A6?I:A2?82? E?DE
2D2E 2D2E
'6?8EEB,E9E :A@D6C:C*=2?4
'2D292B:2D2E:?D2?8
63292C
63292C 63292C
*2?;2?8!6=@32?8
56B@8=:6
%6D:52A2CD:2?6:C6?36B8
E2=:C6!6=@32?8*2BD:6=
,:72D!6=@32?8A252*2BD:6= ,:72D*2BD:6=A252!6=@32?8
Refleksi
Setelah mempelajari materi pada bab ini, Anda tentu
dapat memahami mengenai benda hitam. Anda juga
paham bahwa cahaya juga dapat bersifat seperti partikel
dan partikel bisa bersifat seperti gelombang. Dari
keseluruhan materi yang ada pada bab ini, bagian
manakah yang Anda anggap sulit untuk dipahami? Coba
Anda diskusikan dengan teman atau guru Fisika Anda.
Coba Anda tuliskan juga manfaat mempelajari bab ini.
Diskusikan konsep yang ada di dalamnya bersama teman
Anda.

246. *252A6B:CD:G26767@D@=:CDB:C62:?36C2B:?D6?C:D2C
4292I2A6?I:?2B2??I222
2 C62:?36C2B6?6B8::?6D:6=6DB@?I2?8D6B=6A2C
3 C62:?36C2B646A2D2?6=6DB@?I2?8D6B=6A2C
4 C62:?32?I26=6DB@?I2?8D6B=6A2C
5 646A2D2? 52? ;E=29 6=6DB@? I2?8 D6B=6A2C
C2236C2B
6 6?6B8:I2?8D6BC6B2A@=693292?C62:?36C2B
?6B8: 7@D@? CE2DE 86=@32?8 6=6DB@28?6D:
36B82?DE?8A252
2 646A2D2??I2 5 A2?;2?886=@32?8?I2
3 :?D6?C:D2C?I2 6 CE9E?I2
4 2A=:DE5@?I2
6B:ED :?: I2?8 7@D@??I2 6:=:: 6?6B8: D6B36C2B
252=29
2 C:?2B6B29 5 C:?2B1
3 C:?2BE?8E 6 86=@32?8B25:@
4 C:?2B822
6C2B?I2A2?;2?886=@32?856B@8=:652B:C63E29
6=6DB@?I2?836B86B256?82?6=2;E2?56?82?
P

247. C52?2CC26=6DB@?

248. P

249. M

250. 8
252=29
2
K 5 K
3 K 6 K
4 K
292I2 E=DB2F:@=6D I2?8 5:A6B8E?22? E?DE
6?I:?2B: A6BE22? =@82 6:=:: A2?;2?8
86=@32?8
K =6DB@? I2?8 D6B=6A2C 52B:
A6BE22?=@826:=::6?6B8::?6D:C636C2B
6/ E?8C:6B;252B:=@82D6BC63ED252=29
2 6/ 5
6/
3 6/ 6

251. 6/
4 6/
E26A:?8=@825:36B:2?3652A@D6?C:2==6DB@?
6?E3E 2?@52 56?82? 6=2;E2? / $:2 2CC2
6=6DB@? E2D2??I2 6=2;E2? 6=6DB@? 52A2D
5:DE=:C2?6?;25:
2
5

252. 3
6
4
$:2 C63E29 A62?42B B25:@ 36B52I2

253. G2DD
62?42B2?7@D@?D:2AC6@??I2C632?I2P

254. 3E296?6B8:C2DE7@D@??I2252=29
2
P

255. M

256. $ 5
P

257. M
$
3 P

258. M

259. $ 6 P

260. M
$
4
P

261. M

262. $
#
194 Mudah dan Aktif Belajar Fisika untuk Kelas XII
*6BE22?=@82D6BD6?DE6:=::7E?8C:6B;2
;@E=6 $:2 @?CD2?D2 *=2?4 ! ;@E=6 C6@? 6?6B8:
2C:E7@D@6=6DB@?I2?85:92C:=2?@=694292I2
36B7B6E6?C:/J252=29 ;@E=6
2 !/ 5 !/
3 !/ 6 !/2
4 2!/
*6BE22? CE2DE =@82 6:=:: 7E?8C: 6B;2
P

263. M

264. $ 5:C:?2B: 4292I2 I2?8 A2?;2?8
86=@32?8?I2 ?6B8::?6D:7@D@6=6DB@?
2C:EI2?85:92C:=2?252=29
2
P

265. M

266. $
3

267. P

268. M

269. $
4

270. P

271. M

272. $
5 P

273. M

274. $
6 P

275. M

276. $
'837

277. *2?;2?886=@32?8CE2DE7@D@?P

278. K6?86?2:
CE2DEA6BE22?=@82I2?86?6B8:232?8?I2
6/
$:2P

279. C52?!P

280. M;@E=6C6@?
36C2B6?6B8::?6D:7@D@6=6DB@?252=29
2 P

281. M
;@E=6
3 P

282. M
;@E=6
4 P

283. M
;@E=6
5 P

284. M
;@E=6
6 P

285. M
;@E=6
'837

287. $:2C:?2BE?8E6:=::7B6E6?C:

289. J5:;2DE92?
A252A6BE22?=@82I2?86:=::6?6B8:232?8
2=:E2?DE6?6B8:C:?2BE?8E52?D6D2A2?*=2?4
P

290. M;@E=6C6@?6?6B8::?6D:6=6DB@?I2?8
5:=6A2C252=29
2

291. P

292. M

293. ;@E=6
3
P

294. M

295. ;@E=6
4 P

296. M

297. ;@E=6
5 P

298. M

299. ;@E=6
6 P

300. M

301. ;@E=6

302. B6E6?C:232?8?2DB:EP

304. J 6C2B?I2
A@D6?C:2= A6?896?D: 52=2 F@=D 328: ?2DB:E C22D
5:C:?2B:56?82?4292I2I2?87B6E6?C:?I2P

306. J
252=29
2 / 5 /
3 / 6 /
4 /
#

307. ,636B2CC:?2B56?82?

309. J;2DE9A252=@82
E?8C:6B;2=@82
P

310. M

311. $22A@D6?C:2=96?D:
,-())' )(-'-%52B:6=6DB@?!P

312. M$C6

313. P

314. M

315. 8*6

316. P

317. M

318. 252=29
2

319. / 5 /
3

320. / 6 /
4

321. /
Tes Kompetensi Bab 7
.1.-1-71-789/;'3=3,51.3,'*36

322. !
Radiasi Benda Hitam 195

323. *25286;2=27@D@=:CDB:5:A6B@=698B27:9E3E?82?E2D
2BECI2?8D:3E=D6B9252AD682?82?=:CDB:C6A6BD:
A252 8232B .A2I2 I2?8 5:=2E2? 282B 8B27:
6?;25:8B27:252=29
b
2 6?8EB2?8::?D6?C:D2CC:?2B?I2
3 6?2329:?D6?C:D2CC:?2B?I2
4 6?2:2?7B6E6?C:C:?2B
5 6?EBE?2?7B6E6?C:C:?2B
6 6?882?D:=@82I2?85:C:?2B:
#

324. !B27: I2?8 6?E?;E2? 9E3E?82? 2?D2B2 6?6B8:
:?6D:6=6DB@?7@D@52?:?D6?C:D2C7@D@?A252
AB@C6C7@D@=:CDB:252=29
2 5
3 6
4
#

325. $:2 D6D2A2? *=2?4 P

326. M $C A2?;2?8
86=@32?856B@8=:6CE2DE6=6DB@?I2?836B86B2
56?82?6=2;E2?

327. P

328. C252=29
2 P

329. MK
3 P

330. M
K
4 P

331. M

332. K
5 K
6 K
'837

333. 292I2E?:?86:=::A2?;2?886=@32?8 K
$:2D6D2A2?*=2?4P

334. M$C52?6=2;E2?
4292I2 52=2 BE2?8 92A2 252=29 P

335. C
@6?DE7@D@?4292I2E?:?8252=29
2

336. M8
C
3

337. M

338. 8
C
4

339. M8
C
5

340. 8
C
6

342. 8
C
'837

343. ,63E296=6DB@?5:A6B46A2D@=69CE2DE3652A@D6?C:2=
$:2E2D2?6=6DB@?2CC26=6DB@?52?
!@?CD2?D2*=2?422A2?;2?886=@32?856
B@8=:66=6DB@?:?:52A2D5:?I2D22?56?82?BEEC
2 !
5
!
3
!
6
4
!
#

344. !B27:36B:ED6?E?;E2?9E3E?82?6?6B8::?6D:
2C:E6=6DB@?D6B9252A7B6E6?C:7@D@?
A2526767@D@=:CDB:
$:2@?CD2?D2*=2?4P

345. M$C52?

346. 6/

347. P

348. M

349. ;@E=636C2B252=29
2 P

351. J 5 P

353. J
3

354. P

356. J 6 P

358. J
4

359. P

361. J
#
!232B 36B:ED 252=29 8B27: 9E3E?82? 6?6B8:
:?6D:2C:E7@D@6=6DB@?D6B9252A7B6E6?C:
C:?2BI2?85:8E?22?A2526767@D@=:CDB:
(:=2:A2528B27:D6BC63ED252=29
2
P

362. M$ 5
P

363. M

364. $
3 P

365. M$ 6 P

366. M

367. $
4 P

368. M
$
#

369. E3E?82? 6?6B8: :?6D: 6=6DB@? 52? 7B6E6?C:
A6?I:?2B2?A25286;2=27@D@=:CDB:D6B=:92DA2528B27:
C6A6BD:8232B
Ek
I
Ek
I
Ek
I
Ek
I
Ek
I
Ek (eV)
0, 2
3,7
f0 f
f (Hz)
4 5
f (×1014Hz)
Ek (J)
p
C
D
fA f B
Ek (J)
f (Hz)
I
V
a
0

370. A23:=2@?CD2?D2*=2?4!36C2B?I27E?8C:6B;2
=@82252=29
2
! 5 !

371. 3 ! 6 !

372. 4 !
#
,63E296=6DB@?I2?85:A6B64:=A2523652A@D6?C:2=

373. /A252D23E?892A2E52B222?6?:3E=2?
A2?;2?886=@32?8:?:EC636C2B
2 P

374. M

375. 5 P

376. M

377. 3 P

378. M

379. 6

380. P

381. M

382. 4
P

383. M

384. #
$:252B:62522?5:2?I26=6DB@?A6BD225:A6B46A2D
@=6936?52A@D6?C:2=

385. 52?6=6DB@?=2:?56?82?3652
A@D6?C:2=
A6B32?5:?82? A2?;2?8 86=@32?8 56
B@8=:66=6DB@?6=6DB@?D6BC63EDE?DE3652A@D6?C:2=
36B@B56/252=29
5
2

387. 6
3

388. 4

389. ?6B8::?6D:6=6DB@?I2?8D6B=6A2C52B:A6BE22?
=@82C636C2B

390. 6/ A23:=24292I2A6?I:?2B2?52B:
=E2BI2?85:A6B8E?22?6:=::7B6E6?C:

392. J
36B2A229 7B6E6?C: A6?I:?2B2? I2?8 5:A6B=E2?
CEA2I26?6B8::?6D:6=6DB@?6?;25:
6/
@D@?52B:86=@32?86=6DB@28?6D:56?82?A2?;2?8
86=@32?8K6?E3EC63E296=6DB@?52=2
BE2?8 92A2 ,6D6=29 DE3E2? 7@D@? D6BA2?DE=
56?82?2B29LD6B9252A2B29C6E=2D6?DE2?=29
2 A2?;2?886=@32?87@D@?C6D6=2936BDE3E2?
3 6?6B8:7@D@?C6D6=2936BDE3E2?
*252C63E29:B@C@A6=6DB@?6=6DB@?5:=6G2D2?
A252652?=:CDB:56?82?3652A@D6?C:2=
6/ $:2
5:6D29E:2CC26=6DB@?

393. P

394. M

395. 852?E2D2?
6=6DB@?

396. P

397. M

398. 4@E=@3D6?DE2?=29
2 646A2D2?6=6DB@?C22D6?E3E2?@52
3 A2?;2?886=@32?86=6DB@?
*252 C22D 7@D@? 6?E3E C63E29 6=6DB@? 7@D@?
D6BC63ED36B32=:2B2952B:2B29?I2C6E=2 A23:=2
A2?;2?8 86=@32?8 7@D@? E=2E=2

399. K
D6?DE2?=29
2 A2?;2?886=@32?8?I2C6D6=2936BDE3E2?
3 6?6B8:7@D@?I2?89:=2?8A252C22D36BDE3E2?
-6?DE2?=2936C2B?I26?6B8:A6B56D:I2?85:A2?42B
2?@=69C63E293@=22A:36BA:;2B56?82?5:26D6B
4
196 Mudah dan Aktif Belajar Fisika untuk Kelas XII
TA
TB
I
T
52? CE9E A6BE22? 3@=2 2A: D6BC63ED %
:6D29E:@67:C:6?6:C:F:D2C?I2

400. E?8C: 6B;2 C63E29 =@82 ?2DB:E 252=29
6/
-6?DE2?A2?;2?886=@32?82C:E4292I2I2?8
52A2D6?I63232?D6B;25:?I26767@D@6=6DB@?
*252CE2DEA6B:CD:G27@D@=:CDB:6=6DB@?D6B=6A2C52B:
A6BE22?=@8256?82?6=2;E2?/A252C22D7B6E6?C:
C:?2B I2?8 5:A22: 6?I:?2B: =@82 D6BC63ED
-6?DE2?=296=2;E2?6=6DB@?I2?86=E2B52B:A6B
E22?=@82;:27B6E6?C:C:?2B=E2B5:;25:2?
,63E29 7@D@? 56?82? A2?;2?8 86=@32?8 (
6?23296=6DB@?5:2 @D@?5:923EB2?56?82?
CE5ED C:A2?82?

401. L 52B: 2B29 C6E=2 -6?DE2?
A2?;2?886=@32?87@D@?C6D6=29DE3E2?
*2BD:6= 52A2D 36BC:72D C63282: 86=@32?8 56?82?
C6?5:B:?I26=6DB@?22?52A2D6?E?;E2?C:72DC:72D
:?D6B76B6?C:2D2E5:7B2C:;:25:=6G2D2?A252CE2DE
:C: ED:2? 329G2 6=6DB@? 52A2D 6?E?;E2?
C:72DC:72D D6BC63ED C63282:2?2 92=?I2 CE2DE
86=@32?8

402. A23:=2 7E?8C: 6B;2 CE2DE =@82 252=29

403. 6/
36B2A229 A2?;2?8 86=@32?8 A6?I:?2B2? I2?8
5:A6B=E2?@=69=@82D6BC63EDCEA2I26?6B8::?6D:
6=6DB@?I2?852A2D5:=6A2C2?52B:A6BE22?=@82
D6BC63EDC636C2B6/
;'1-5*683=3'*6.098)*3,38*58
$:252B:62522?5:26=6DB@?5:A6B46A2D36BDEBED
DEBED@=693652A@D6?C:2=

404. F@=D52?
F@=DA6B32?5:?82?A2?;2?886=@32?856B@8=:6?I2
252=29
2

405. 5
3

406. 6
4
#
2B:8B27:36B:ED9E3E?82?2?D2B2:?D6?C:D2C6?6B8:
I2?85:A2?42B2?@=69A6BE22?36?52D6B9252A
A2?;2?886=@32?8 I2?85:A2?42B2?252=29
2 52?
3 52?
4 52?
5 52?
6 52?