160
Mudah dan Aktif Belajar Fisika untuk Kelas X
B. Perpindahan Kalor
8:08=68=40A0:0838?4;C:0=:0;G0=6140A0;3080?8:? 030?40=0A0=A4?0=2808C;0C;0:0;3080?8:?14?8=307
:4?0=28B4?0B08:4C380=:0;308?0=28B4A41CB14?8=307:408 4?8=3070=:0;B4903830814=3014AC7CB8=668?0=0A:414=30
14AC7C;41874=30738=68=4=30G0=6?0=0A4148:0=:0;:4 ?03014=30G0=638=68=40=308=G0:0;B830:30?0B14?8=3070:0=
AC;8BC=BC:40A0:08A4101:0;3080?8:?B830:30?0B14?8=307 :408
30 B860 14=BC: ?4?8=3070= :0; G08BC 70=B00= +0;80=30=?0=200=
1. Perpindahan Kalor Secara Konduksi
8A0;:0==3040=0A:0=A0;07A0BCC9C=610B0=6;60A4?4B8 .3
4=BC=G0?0B8:4;?0B8:4;?030C9C=6;60G0=638?0=0A8
1464B0;418724?0B40:8=14A09C;07:0;G0=638148:0=:4?030 C9C=6 ;60 8BC A40:8= 24?0B 64B00= ?0B8:4;=G0 410680= 4=468
:8=4B8:G0=6388;8:8?0B8:4;G0=61464B0B4A41CB38148:0=:4?030 ?0B8:4;?0B8:4; 38 34:0B=G0 4;0;C8 BC1C:0= :810B=G0 ?0B8:4;
?0B8:4;G0=638BC1C:8BC8:CB1464B0348:80=A4B4CA=G078=660 64B00=?0B8:4;A0?08:4C9C=6;60G0=6B830:38?0=0A8
4010B0=64B00=?0B8:4;B4A41CB38A4B0834=60=?4010B0= :0;308C9C=6;60G0=638?0=0A8A0?08:4C9C=6;60G0=6B830:
38?0=0A8:810B=G0C9C=6;60G0=6B830:38?0=0A84=9038?0=0A 010B0=:0;8=8B830:38A4B0834=60=?4?8=3070=?0B8:4;?0B8:4;
;60 38A41CB
0B0C .3 4?4;870B:0=A410B0=6;6034=60=;C0A?4=0?0=6
30=?0=90=610B0=6 38?0=0A:0=A0;07A0BCC9C=6=G0030?48AB8E0 B4A41CB:0;0:0=4010B:4C9C=6A414;07:0=0=G0=6AC7C=G0
;41874=307430A0:0=?4=4;8B80=G0=6B4;0738;0:C:0=38?4;47 107E0?4?8=3070=:0;A4200:=3C:A81460=BC=6?03094=8A;60
;C0A ?4=0?0=6 ?4=670=B0 :0; ?414300= AC7C 308 C9C=6C9C=6 ;60B4?0B:0;4010BA4B0?0=90=690;0=G0=638;0;C8;47:0;
4?8=3070=:0;A4B80?A0BC0=E0:BC38CCA:0=A410608148:CB
Gambar 7.15
Contoh perpindahan kalor secara konduksi.
Gambar 7.16
Hantaran kalor T
1
T
2
A
J J
J 4B40=60=
:0;G0=64010B?4A0BC0=E0:BC A0B0CE0BB :458A84=:=3C:A8B40;H0B A0B0C,
;C0A?4=0?0=610B0=6 ?0=90=610B0=6
161
Kalor
-
30=-4?4;870B:0=:458A84=:=3C:A8B40; H0B1C:0=;6030=;60
. .4; A
0B0407 4B=
020 0GC:48=6
01CA BG50
08=B410; 300
- 458A84==3C:A840;-0B
C:0=600B00B0 . .4;
40: 41060
;C8=8C C=8=60=
810; 090
0:A0 -
458A84==3C:A840;60 0B00B0
2. Perpindahan Kalor Secara Konveksi
030 A00B =30 40=0A:0= 08 38 30;0 ?0=28 :0; 0:0= 14?8=307 308 30A0 ?0=28 :4 ?4C:00= 08 A4200 :=D4:A8
4?8=3070=:0;A4200:=D4:A838A4B08640:0=0AA00B0C640:0= ?0B8:4;?0B8:4;H0B?40=B00=G0=D4:A870=G0B49038?030H0BG0=6
30?0B4=60;85;C830 303C0200?4?8=3070=:0;4;0;C870=B00=:=D4:A8G08BC
:=D4:A8A42000;080730=:=D4:A8?0:A0 a.
Konveksi Alamiah 8A0;:0==3040=0A:0=A4?0=2808A4?4B8?030.3
4B4;07 08 38 10680= 10E07 ?0=28 4=480 :0; 08 B4A41CB 0:0= 4C08A478=6600AA094=8A=G0;4187:428;308?0300AA094=8A0838
10680= 0B0A 414300= 0AA0 94=8A B4A41CB 4=60:810B:0= ?0B8:4; ?0B8:4;08G0=6140AA094=8A;4187:428;0:0=14640::40B0A
4?0BG0=638B8=660;:0=?0B8:4;08G0=6140AA094=8A;4187:428; 0:0=B48A8;47?0B8:4;08G0=6140AA094=8A;418714A048AB8E0
B4A41CB14;0=6AC=6B4CA4=4CAA478=660?0B8:4;?0B8:4;0830;0 ?0=28 14?CB0 =08: 30= BCC= ;80=0;80= ?0B8:4; G0=6 14640:
B4A41CB38A4B0834=60=?4?8=3070=:0;4?8=3070=:0;34=60= 4=60;8:0=?0B8:4;?0B8:4;08A4?4B88=838A41CB+
=D4:A8 0;0807 10=G0: 389C?08 38 ?018:?018: G0=6 4=6 6C=0:0=241=60A0?0A70A8;?410:00=48;8:80AA094=8A;4187
:428; 308?030 0AA0 94=8A C300 38 A4:8B0=G0 :810B=G0 60A 70A8; ?410:00=0:0=4=60;8:40B0A4?0BG0=638B8=660;:0=;4760A
70A8;?410:00=0:0=388A8;47C300A4:8B0G0=648;8:80AA094=8A ;418714A0308?0300AA094=8A60A70A8;?410:00=
=68=;0CB30=0=68=300BB490381430A0:0=:=D4:A80;0807 C300=68=;0CB30=0=68=300BG0=6380=500B:0==4;0G0=C=BC:
14;0G0B490384;0;C8:=D4:A80;0807C300380=0?0=0A38?8=307 :0=308AC0BCB4?0B:4B4?0B;08=34=60=?4640:0=?0B8:4;G0=6
Berapa kalor yang diperlukan untuk mengubah 500 g es dari –10°C
menjadi uap bersuhu 120°C kalor lebur, dan kalor uap dapat dilihat
pada Tabel 7.2 dan Tabel 7.3.
Tantangan
untuk Anda
Gambar 7.17
Peristiwa konveksi alamiah
Sumber:
Fisika Universitas, 2002
Sumber:
Fisika Universitas, 2002
162
Mudah dan Aktif Belajar Fisika untuk Kelas X
38?8=307:0=030A80=6708300B0=;418724?0B?0=0A308?030;0CB A478=660C300?0=0A380B0A300B0==08:30=B4?0B=G03860=B8:0=
C30038=68=3080B0A;0CB8=8G0=638A41CB0=68=;0CB0300;0708 B49038A410;8:=G000B0=;418724?0B38=68=308?030;0CBA478=660
C300380B0A;0CB=08:30=B4?0B=G03860=B8:0=;47C3003080B0A 300B0=G0=638A41CB0=68=300B
b. Konveksi Paksa
=D4:A8 ?0:A0 10=G0: 386C=0:0= ?030 A8AB4 ?4=38=68= 4A8= 8A0;=G0?0304A8=18;4A8=:0?0;;0CB4A8=384A4;AB0A8=430=
:8?0A0=68= =D4:A8 ?0:A0 A4?4B8 ?030 .3 38?0:08 30;0 A8AB4
?4=38=68=4A8=18;84=60;838A4:8B0C0=64A8=4;0;C8?8?0 ?8?03810=BC;47A41C07??008,0;G0=638B480
4A8=18;30870A8;?A4A?410:00=4=20?08AC7C
I030 AC7C8=84C=6:8=:0=4A8=18;4C084;4187810B0A:400=0=
30=4=60:810B:0=10680=10680=4A8=18;4=9038;4074CA0:0= ?4B00G0=6A48=6389C?08030;07?030:?A8;8=344A8=4=9038
4;4=6:C=64=60C7148:CB=G0D8A:A8B0A8=G0:?4;C0A4=9038 4=3074=24
0=0A?0304A8=18;14?8=307;47A8:C;0A8084=C9C:40 380B 300 38=68= 308 ;C0 4A8= 38B08: ;47 A41C07 :8?0A C=BC:
4=38=68=:0= 08 ?030 0380B A478=660 08 G0=6 38=68= 8=8 :410;8 4=60;8 30= 14A4=BC70= 34=60= 1;:1;: 4A8= C=BC: 4=6C;0=6
A8:C;0A8148:CB=G0 0385C=6A80380B030;074=9060AC7C4A8= 060B830:4;0?0C810B0A?0=0AG0=6388H8=:0=
C;07 4=468 :0; ?4 A0BC0= E0:BC G0=6 38B480 ;47 5;C830 A4:8B0=G0 A4200 :=D4:A8 030;07 A410=38=6 34=60= ;C0A ?4C:00=
14=30G0=614A4=BC70=34=60=5;C83034=60=1430AC7C
t
4200 0B40B8A38BC;8A
Q t
0B0C J
4B40=60= 9C;07:0;?4A0BC0=E0:BC A
:458A84=:=D4:A8B40; A I
;C0A?4=0?0=6?4?8=3070=:0;
t
?414300=AC7CG0=638?0=0A834=60=AC7C5;C830I 8;08:458A84=:=D4:A8B40;1460=BC=6?03014=BC:30=:43C3C:
0=?4C:00=0894=8A5;C830G0=614A4=BC70=34=60=?4C:00= J
C7CC30030;0A41C07C0=60=A414A0 IA430=6:0=AC7C?4C:00=94=34;0 ?030C0=60=B4A41CB I40?0;09C:0;G0=638B480;4794=34;0:020A4;C0A
98:0:458A84=:=D4:A8C300A00B8BCK
J
:0;A I
Contoh
7.7
pipa-pipa kecil
kipas pompa air
saluran air dalam
mesin
Gambar 7.18
Sistem peredaran pendingin air pada mobil.
Misalkan Anda menyeduh secangkir kopi dengan air panas,
lalu Anda mengaduknya dengan sendok yang terbuat dari logam.
Mengapa sendok itu terasa lebih panas dibandingkan jika Anda
mengaduknya menggunakan sendok yang terbuat dari plastik?
Tantangan
untuk Anda
Kategori