Izibonelo ezi-5 zezinkinga zokushisa
1. Ithini elinesisindo esingamakhilogremu ama-2 linokushisa okuthile okungu- 130 J.kg -1 C -1 . Inani lokushisa okumuncwa yithini ukuze liphakamise izinga lokushisa lalo kusuka ku-50 o C kuya ku-100 o C….
Ingxoxo
Kuyaziwa ukuthi:
IMisa (m) = 2 kg
Ukushisa okuqondile kwethini (c) = 130 J.kg -1 C -1
Ukushintsha kwezinga lokushisa (Δ T) = 100 o C – 50 o C = 50 o C
Umbuzo: Ukushisa (Q) kumuncwa yithini
Impendulo:
Ifomula yokushisa:
Q = mc Δ T
Incazelo: Q = ukushisa, m = isisindo, c = ukushisa okuthile, Δ T = ushintsho lokushisa
Ukushisa kumuncwa yithini:
Q = (2 kg)(130 J.kg -1 C -1 )(50 o C)
Q = (100)(130)
Q = 13000 Joule
Q = 1,3 x 10 4 amaJoules
2. Ithusi elinokushisa okuthile okungu-390 J kg -1 o C -1 libhekana nokushintsha kwezinga lokushisa okungu-40 o C. Uma ukushisa okumuncwa yithusi ngesikhathi sokushintsha kwezinga lokushisa kungama-calories angu-200, khona-ke isisindo sethusi...
Ingxoxo
Kuyaziwa ukuthi:
Ukushisa okuqondile kwethusi (c) = 390 J kg -1 o C -1
Ukushintsha kwezinga lokushisa (Δ T) = 40 o C
Ukushisa (Q) = ama-Joules angu-40
Umbuzo: Isisindo (m) sethusi
Impendulo:
Q = mc Δ T
40 = (m)( 390 )(40 o C)
40 = (m)(390 )(40)
40 = (m)( 390 )(4)
40 = (m)( 1560 )
m = 40/1560
m = 0,026 kg
Isisindo sethusi singamagremu ayi-26.
3. Amanzi anesisindo esingamagremu angu-20 anokushisa okuthile okungu-1 cal g -1 o C -1 ekuqaleni anokushisa okungu-30 o C. Thola ushintsho ekushiseni kwamanzi uma inani lokushisa elimuncwa amanzi lingama-calories angu-300!
Ingxoxo
Kuyaziwa ukuthi:
Isisindo (m) = 20 gr
Izinga lokushisa lokuqala (T1 ) = 30 o C
Ukushisa kwamanzi okuqondile (c) = 1 cal gr -1 o C -1
Ukushisa (Q) = 300 cal
Kubuziwe: Izinguquko ekushiseni kwamanzi
Impendulo:
Q = mc Δ T
Q = mc (T 2 – T 1 )
Ama-calories angu-300 = (20 gr)( 1 ama-calories gr -1 o C -1 )(T 2 – 30 o C)
300 = (20)(1)(T 2 - 30)
300 = 20 (T 2 – 30)
300 = 20 T 2 – 600
300 + 600 = 20 T 2
900 = 20 T 2
I-T 2 = 900 / 20
I-T 2 = 45 o C
Izinguquko zokushisa:
Δ T = 45 o C – 30 o C
ΔT = 15 o C
4. Inani lokushisa elidingekayo ukuze kwehliswe izinga lokushisa elingu-4 kg loketshezi olunokushisa okuthile okungu-500 J/kg K kusuka ku-40 oU-C uba ngu-20 oU-C…
A. 20 kJ
B. 30 kJ
C. 40 kJ
D. 50 kJ
E. 60 kJ
Ingxoxo:
I-Diketahui :
IMisa (m) = 4 kg
Ukushisa okuqondile (c) = 500 J/kg K = 500 J/kg Co
Ukushintsha kwezinga lokushisa (i-delta T) = 40 oC - 20 oC = 20 Co
Kubuziwe :
Ukushisa (Q)
Jawab :
Ifomula Yokushisa :
Q = (m)(c)(delta T)
Q = (4)(500)(20) = 40.000 Ama-Joules = 40 kJ
kJ = kilo Joule
Impendulo efanele ngu-C.
5. Into eqinile enesisindo esingu-2 kg ishiswa kusukela ekushiseni okungu-30oU-C uba ngu-100oC, idinga ukushisa okungu-7 × 105 UJoule. Ukushisa okuthile kwale nto…
A. 400 J/kg K
B. 500 J/kg K
C. 700 J/kg K
D. 1000 J/kg K
E. 5000 J/kg K
Ingxoxo:
I-Diketahui :
IMisa (m) = 2 kg
Ukushisa (Q) = 7 × 105 J = 700.000 J
Ukushintsha kwezinga lokushisa (i-delta T) = 100 oC - 30 oC = 70 Co
Kubuziwe :
Ukushisa okuthile (c)?
Jawab :
c = Q / m T
c = 700.000 J / (2 kg)(70 Co) = 700.000 J / 140 kg Co
c = 5000 J/kg Co
c = 5000 J/kg K
Impendulo efanele ngu-E.
