Mudah dan Aktif Belajar Fisika untuk Kelas XII
178
2. Spektrum Radiasi Benda Hitam
:2CE2DE36?52A252D5:A2?2C2?36?52D6BC63ED22?62? 42B2?B25:2C:2=B52=236?DECA6DBE86=32?86=6DB28?6D:
56?82?A2?;2?886=32?852?7B6E6?C:I2?836B3652 252CE9EI2?8 =63:9D:?88:22?D6B52A2DB25:2C::?7B26B29I2?8D:5252A2D5:=:92D
D6D2A:52A2D5:B2C22?A2?2C?I2 2=:?:52A2D5:22D:A252C6AD?8 =82I2?85:A2?2C2?9:?8826?42A2:CE9E
8236BA:;2B
56?82?G2B?2E?:?82D2E6AED:9AED:92? +25:2C:86=32?8I2?8 5:A2?42B2?6E5:2?5:=6G2D2?6=2=E:46=29282B5:A6B=6936B2C
86=32?8I2?8C6A:DC6A6BD:D2A2A25226 6?82? 56::2? 86=32?8 22? D6B5:CA6BC: 6?EBED A2?;2?8
86=32?8C6D:2ACA6DBE 6D6DBI2?8D6B=:92DA2528232B52A2D 5:86C6B86C6B6?EBEDCE5ED56F:2C:86=32?8D6B5:CA6BC: 6B4322?
:?:5:=2E2?A252CE9E36?529:D2I2?836B36523652 6?822D2? A252:?D6?C:D2CCA6DBEB25:2C:6?892C:=2?52D2I2?85:DE?;E2?
A25226 26
6?E?;E2?329G22A23:=2CE9ECE2DE36?52D6BEC
5:?2:2?:?D6?C:D2CB6=2D:752B:CA6DBE4292I2I2?85:A2?42B2??I2 36BE329 ?:6?I63232?A6B86C6B2?52=2G2B?2G2B?:CA6DBEI2?8
D6B22D:I2?852A2D5:8E?22?E?DE6?2C:BCE9ECE2DE36?52 -6B=:92D ;E82A6B86C6B2?A2?;2?886=32?82C:E
2C
,62:?D:?88: CE9ECE2DE36?52
2C
C62:?36B86C6B62B29A2?;2?886=32?8 I2?8=63:9A6?56
82B?52=63:96292:EE6B86C6B2?0:6?A6B92D:2? 2636B:ED
Gambar 7.3
Spektrum warna pijar suatu benda panas berubah terhadap suhunya.
Gambar 7.2
Percobaan untuk mengamati spektrum radiasi benda hitam.
Warna
1.500 1.400
1.300 1.200
1.100 1.000
900 800
700 600
500 putih
kuning muda kuning
oranye merah-oranye
merah ceri merah tua
baru tampak
T ºC
I Wbm
2
m T
2
T
1
T
1
benda hitam
prisma celah
spektrum gelombang
detektor
Gambar 7.4
Grafik pergeseran panjang gelombang maksimum pada
saat suhu berubah dari T
1
ke T
2
.
; :6D29E:
=E2CA6BE22? P
M
CE9EED=2 6:C:F:D2C2?882A36?529:D2
P
M
2I22=BB25:2C:I2?85:A2?42B2?=69=2AEA:;2B5:9:DE?86=2=E:6723 ?
I2:DE
P
M
03 P
M
2I22=BB25:2C::?:252=2952B:52I2=:CDB:I2?85:36B:2?6=2AEA:;2B 25:0P
=:CDB: =:CDB:
-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
DIUNDUH DARI: WWW.BUKUPAKET.COM Sumber buku bse.kemdikbud.go.id
Radiasi Benda Hitam
179
2B: 26 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?329G292C:=2=:2?D2B2
2C
52?CE9EED=2 6BEA22?3:=2?82??CD2?C6A6BD:A2526723?52?3:=2?82?
?CD2?A252A6BEEC2?EE6B86C6B2?0:6?36B?:=2:
P
M
EE6B86C6B2?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?8D6BC63ED52A2D5: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?M22?5:A6B=69
2C 2C
P
M 2C
25:A2?;2?886=32?82C:EB25:2C:D6B2=252=29P
M
I T
1
T
2
T
3
6B52C2B2?8B27::?D6?C:D2CB25:2C: D6B9252A A2?;2?8 86=32?8 C6A6BD:
5:DE?;E2?A2528232B5:C2A:?8 3282:2?2299E3E?82?2?D2B2CE9EED=2
52? ;
2B:8B27:A2528232B5:C2A:?85:A6B=69 329G2EBED2?A2?;2?886=32?8E?DE:?D6?C:D2CB25:2C:2C:E252=29
6B52C2B2?9EEA6B86C6B2?0:6?6723?5:A6B=69 2D2E
25: 5:A6B=69
Contoh
7.4
3. Pendekatan Teori Rayleigh–Jeans
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