Kunzwisisa Nheyo dzeVatema
Kana tikasanganisa mvura inopisa neinotonhora mumudziyo wakavhurika (semuenzaniso, bhaketi), kupisa kunopfuudzwa kubva mumvura inopisa kuenda kumvura inotonhora. Nekuti bhaketi rakavhurika, kumwe kupisa kunopfuudzwa kumhepo. Mudziyo unodziyawo. Kupisa kunoburitswa nemvura inopisa hakungonyurwi nemvura inotonhora chete asiwo nemhepo nemudziyo. Muchiitiko ichi, bhaketi haisi yega.
Patinosanganisa mvura inopisa neinotonhora mu thermos yakavharwa, kupisa kunopfuudzwa kubva mumvura inopisa kuenda kumvura inotonhora. Thermos sisitimu yakaparadzana , saka hapana kupisa kunopfuudzwa kumhepo kana ku thermos. Kupisa kunoburitswa nemvura inopisa kunongotorwa nemvura inotonhora kusvika musanganiswa wasvika pakuenzana kwekupisa.
Nheyo yaBlack inoti muhurongwa hwakavharwa hwakaparadzana, kupisa kunoburitswa nechinhu chinodziya zvakanyanya = kupisa kunotorwa nechinhu chinodziya zvishoma.
Fomura yekutanga yeBlack
Qyadzimwa =Qsveta
Tsananguro: Qyadzimwa = kupisa kunoburitswa nechinhu chinodziya zvakanyanya, Qsveta = kupisa kunotorwa nezvinhu zvinopisa zvishoma.
Muenzaniso wemibvunzo mikuru yeBlack
1. Chidimbu chesimbi inopisa ine huremu hwe1 kg uye tembiricha ye100 oC inoiswa mumudziyo une mvura ine huremu hwe2 kg uye tembiricha ye20 oC. Tembiricha yekupedzisira yemusanganiswa ndeyei? Kupisa kwesimbi chaiyo = 450 J/kg Co, kupisa kwemvura chaiyo = 4200 J/kg Co.
Kukurukurirana:
Zvinozivikanwa :
m simbi = 1 kg, Tbesi = 100 oC, m mvura = 2 kg, Tmhepo = 20 oC, c simbi = 450 J/kg Co, c mvura = 4200 J/kg Co.
Akabvunzwa :
Musanganiswa weT?
Jawab :
Simbi ine tembiricha yakakwira kupfuura mvura saka simbi inoburitsa kupisa, mvura inotora kupisa.
(m)(c)(delta T) = (m)(c)(delta T)
(1)(450)(100-T) = (2)(4200)(T-20)
(450)(100-T) = (8400)(T-20)
45000 – 450T = 8400 T – 168000
45000 + 168000 = 8400 T + 450 T
213000 = 8850 T
T = 213000 : 8850
T = 24 oC
Suhu Tembiricha yekupedzisira yemusanganiswa wesimbi inopisa nemvura inotonhora kana zvese zviri mukupisa kwemuviri i24. oC.
2. 2015/2016 SMA/MA Fizikisi Mubvunzo weNyaya yeFizikisi Nhamba 20
Magiramu makumi manomwe nemashanu emvura patembiricha ye0 o C inosanganiswa nemagiramu makumi mashanu emvura kuitira kuti tembiricha yemusanganiswa ive 40 o C, saka tembiricha yekutanga yemagiramu makumi mashanu emvura...
A. 125 o C
B. 120 o C
C. 110 o C
D. 100 o C
E. 80 o C
Kukurukurirana
Zvinozivikanwa kuti:
Huremu hwemvura 1 (m1 ) = 75 magiramu
Tembiricha yekutanga yemvura 1 (T 1 ) = 0 o C
Huremu hwemvura 2 (m2 ) = 50 magiramu
Kupisa kwekupedzisira kwemusanganiswa (T) = 40 o C
Mayuniti ehukuru akafanana saka hapana chikonzero chekushandura.
Zvinodiwa: Tembiricha yekutanga yemvura 2 (T 2 )
Mhinduro:
Nheyo yaBlack inoti muhurongwa hwakavharwa hwakaparadzana, kupisa kunoburitswa nechinhu chinodziya zvakanyanya kwakaenzana nekupisa kunonyudzwa nechinhu chinodziya zvishoma.
Q yaburitswa = Q yabatwa
m 1 c ( Δ T 1 ) = m 2 c ( Δ T 2 )
Kupisa kwemvura kwakafanana saka c inobviswa mu equation.
m 1 ( Δ T 1 ) = m 2 ( Δ T 2 )
(75)(40 – 0) = (50)(T 2 – 40)
(75)(40) = (50)(T 2 - 40)
3000 = 50 T 2 - 2000
3000 + 2000 = 50 T 2
5000 = 50 T 2
T 2 = 100
Mhinduro chaiyo ndiD.
3. 2015/2016 SMA/MA Mubvunzo weNyaya yeFizikisi Nhamba 20
Simbi ye200 gram inodziiswa kusvika 120 o C yozoiswa mumagiramu zana emvura patembiricha ye30 o C. Mushure mekuenzana, tembiricha yemusanganiswa inova 60 o C. Kana kupisa kwemvura kuri 4200 J.kg -1 o C -1 , saka kupisa kwesimbi...
A. 10,5 J.kg -1o C -1
B. 105 J.kg -1o C -1
C. 150 J.kg -1o C -1
D. 1050 J.kg -1o C -1
E. 1500 J.kg -1o C -1
Kukurukurirana
Kushandurwa kwemayuniti ehuremu kubva pamagiramu kuenda kumakirogiramu (International System of Units)
Zvinozivikanwa kuti:
Huremu hwesimbi (m 1 ) = 200 magiramu = 0,2 kg
Kupisa kwesimbi (T 1 ) = 120 o C
Huremu hwemvura (m2 ) = 100 magiramu = 0,1 kg
Kupisa kwemvura (T 2 ) = 30 o C
Kupisa kwekupedzisira kwemusanganiswa (T) = 60 o C
Kupisa kwemvura chaiyo (c 2 ) = 4200 J.kg -1 o C -1
Akabvunzwa: Kupisa kwesimbi chaiyo (c 1 )
Mhinduro:
Q yaburitswa = Q yabatwa
m1 c1 (ΔT1) = m2 c2 (ΔT2)
(0,2)(c 1 )(120 – 60) = (0,1)(4200)(60 – 30)
(0,2)(c 1 )(60) = (0,1)(4200)(30)
12 c 1 = 12600
c 1 = 12600 / 12
c 1 = 1050
Mhinduro chaiyo ndiD.
4. Mibvunzo yebvunzo dzenyika dzeSMA/MA dzegore ra2018
250 ml yemvura inopisa (100 o C) inodururwa mupoto ine 400 ml yemvura patembiricha ye35 o C. Mushure mekunge kupisa kwaenzana, tembiricha yemusanganiswa inova… (kupisa kwemvura chaiyo 1,0 cal.gr -1 . o C -1 )
Kukurukurirana
Zvinozivikanwa:
Kupisa kwemvura inopisa = 100 o C
Huwandu hwemvura inopisa = 250 ml = 0,25 litre = 0,25 dm 3 = (0,25)(1000 cm 3 ) = 250 cm 3
Kupisa kwemvura inotonhora = 35 o C
Huwandu hwemvura inotonhora = 400 ml = 0,4 litre = 0,4 dm 3 = (0,4)(1000 cm 3 ) = 400 cm 3
Kupisa kwemvura chaiyo = 1,0 cal.gr -1 . o C -1
Kuwanda kwemvura = 1 gr/ cm3
Akabvunzwa: Kupisa kwemusanganiswa
Mhinduro:
Verenga huwandu hwemvura inopisa neinotonhora uchishandisa fomura yekuwanda:
m = ρ V
m = huremu, ρ = kuwanda, V = vhoriyamu
Huremu hwemvura inopisa: m = ρ V = ( 1 gr/cm 3 )(250 cm 3 ) = 250 magiramu
Huremu hwemvura inotonhora: m = ρ V = ( 1 gr/cm 3 )(400 cm 3 ) = 400 magiramu
Verenga tembiricha yemusanganiswa uchishandisa fomura yeBlack's principle:
Kupisa kunonyudzwa nemvura inotonhora = kupisa kunoburitswa nemvura inopisa
mc Δ T = mc Δ T
Kupisa kwacho kwakafanana saka kunobviswa kubva mu equation.
m Δ T = m Δ T
(400)(T-35) = (250)(100-T)
400T – 14000 = 25000 – 250T
400T + 250T = 25000 + 14000
650T = 39000
T = 39000 / 650
T = 60 o C
