Tauira o te miihini wera (te whakamahinga o te ture tuarua o te thermodynamics)

9 Ngā tauira o ngā raruraru o te miihini wera (te whakamahinga o te ture tuarua o te thermodynamics)

1. I roto i te huringa kotahi, ka mimitihia e te miihini te 3000 Joule o te wera mai i te puna wera-teitei, ā, ka panaia te 1000 Joule o te wera ki te puna wera-iti. Tātaihia te whai huatanga o te miihini wera!

Kōrero
Mīhini wera Kāore te kupu "carnot" i roto i ngā pātai o tēnei whārangi i rite ki te miihini Carnot. He miihini wera pai te miihini Carnot, ā, he ariā anake tōna noho. He rerekē, ko te miihini wera e kōrerohia ana i roto i tēnei pātai he miihini wera tūturu, ehara i te miihini wera ariā (te miihini Carnot).
E mōhiotia ana :
Te wera e mimitia ana (Q_H) = 3000 Joule
Te wera i tukuna (Q_L) = 1000 Joule
Te mahi i whakaputaina e te mīhini (W) = 3000 – 1000 = 2000 Joules
I pātaihia Te whai huatanga o te miihini wera (e)
Whakautu :

2. Ka whakaputahia e te miihini wera he 2000 Joule o te mahi, ā, ka whakakorea e ia he 500 Joule o te wera i roto i te huringa kotahi. Ko te whai huatanga o te miihini ko…

Kōrero
E mōhiotia ana :
Te mahi i whakaputaina e te mīhini (W) = 2000 Joules
Te wera i tukuna (Q_L) = 5000 Joule
Te wera e mimitia ana (Q_H) = 2000 + 5000 = 7000 Joule
I pātaihia Te whai huatanga o te miihini wera (e)
Whakautu :

3. Ko te whai huatanga o te miihini waka he 30%. Mena ka puta i te miihini he 10.000 Joule o te mahi mō ia huringa, e hia te nui o te wera ka panaia e te miihini mō ia huringa?
Kōrero
E mōhiotia ana :
Whai huatanga (e) = 30% = 30/100 = 0,3
Te mahi i whakaputaina e te mīhini (W) = 3000 Joules
I pātaihia : Te wera e marara ana i te miihini i ia huringa (Q_L)
Whakautu :
Tātaihia te wera i mimitia (Q_H) mā te whakamahi i te tātai whai huatanga (e) o te miihini wera:
Te wera e marara ana i ia huringa (Q_L) = te wera i mimitia (Q_H) – mahi i hangaia (W)
Q_L = 10.000 Joule – 3000 Joule
Q_L = 7000 Joule

Te whai huatanga o ngā miihini wera, ngā miihini Carnot

4. Ka mimitihia e te mīhini wera te 3.000 Joule o te wera mai i tētahi puna wera-teitei, ā, ka panaia te 2.400 Joule ki tētahi puna wera-iti. Ko te whai huatanga o te mīhini ko ….
A. 10%
B. 15%
C. 20%
D. 30%
E. 40%
Kōrero:
E mōhiotia ana :
Q_H = 3000 Joule, Q_L = 2400 Joule.
I pātaihia :
Te whai huatanga (e) o te miihini wera?
Whakautu :
Ko te whakautu tika ko C.

5. He 300 te pāmahana o te pūngao wera o tētahi mīhini Carnot ^oC me te puna pāmahana iti 80 ^oC. Ko te whai huatanga o te mīhini ko…
A. 38%
B. 45%
C. 50%
D. 58%
E. 67%
Kōrero:
E mōhiotia ana :
T_L = 80^oC = (80 + 273) K = 353 K
T_H = 300^oC = (300 + 273) K = 573 K
Mena e mōhiotia ana te pāmahana i roto i ngā waeine Celsius, me huri ki ngā waeine Kelvin (ko Kelvin te Pūnaha Ao mō ngā waeine pāmahana).
I pātaihia :
Te whai huatanga (e) o te miihini Carnot?
Whakautu :

Ko te whakautu tika ko A.

6. Ko te pāmahana teitei o te puna wai miihini Carnot he 600 K, ā, ko tōna whai huatanga he 60%. Hei whakatutuki i te whai huatanga 70%, me...
A. 500 K
B. 800 K
C. 1000 K
D. 1200 K
E. 1500 K
Kōrero:
E mōhiotia ana :
Raraunga 1: T_H = 600 K, e = 60%
Raraunga 2: T_H = …. K ?, e = 70 %
I pātaihia :
Te pāmahana teitei (T_H)
Whakautu :
Whakamahia te raraunga 1 hei tatau i te pāmahana iti (T_L).
Whakamahia te T_L me ngā raraunga 2 hei tatau i te pāmahana teitei (T_H):
Hei whakatutuki i te 70% o te pai o te whakamahinga, ko te pāmahana teitei = 800 Kelvin.
Ko te whakautu tika ko B.

7. Tirohia te kauwhata PV o te miihini Carnot i raro nei. Mena ko W = 5000 Joules, ko te nui o te wera e tukuna ana e te miihini mō ia huringa ko...
A. 2.315 Joules
B. 3.475 Joules
C. 3.750 Joule
D. 5.000 Joule
E. 5.600 Joule

Kōrero:
E mōhiotia ana :
W = 5000 Joule
T_H = 780 K
T_L = 320 K
I pātaihia :
Q₂ ?
Whakautu :
Te whai huatanga o te miihini Carnot:
e = 1 – (T_L/T_H) = 1 – (320/780) = 1 – 0,41 = 0,59
E 59% anake o te wera e whakamahia ana hei mahi. Whakamahia ēnei raraunga hei tatau i te wera e mimitihia ana e te miihini Carnot (Q₁).
(0,59)(Q₁) = 5000 Joule
Q₁ = 5000 Joule/0,59 = 8475 Joule
Ko te nui o te wera e mimitihia ana e te mīhini he 8475 Joules.
Te nui o te wera e tukuna ana e te miihini mō ia huringa:
W = Q₁ - Q₂
5000 Joule = 8475 Joule – Q₂
Q₂ = 8475 Joule – 5000 Joule
Q₂ = 3475 Joule
Ko te whakautu tika ko B.

8. Tirohia te hoahoa PV o te miihini Carnot i raro nei! Mena ka mimiti te wera (Q₁) = 8000 Joules, kāti ko te mahi i mahia e te miihini Carnot ko…
A. 1640 J
B. 4720 J
C. 5640 J
D. 6270 J
E. 8840 J

Kōrero:
E mōhiotia ana :
Q₁ = 8000 J
T_H = 820 K
T_L = 380 K
I pātaihia :
W?
Whakautu :
Te whai huatanga o te miihini Carnot:
e = 1 – (T_L/T_H) = 1 – (380/820) = 1 – 0,46 = 0,54
E 54% anake o te wera e whakamahia ana hei mahi. Whakamahia ēnei raraunga hei tatau i te mahi i mahia e te miihini Carnot (W).
(0,59)(8000) = 4720 Joule
Ko te mahi i mahia e te miihini Carnot he 4720 Joules.
Ko te whakautu tika ko B.

9. Ka mahi te miihini Carnot i waenganui i te puna wera o te 520 ^oC me te puna matao 110 ^oC. Mena ka mimiti te mīhini i te 3000 Joule o te wera mai i te puna wera, ko te nui o te wera i peia atu i te mīhini ko...
A. 450 joule
B. 800 joule
C. 1000 meneti
D. 1200 joule
E. 1440 joules
Kōrero:
E mōhiotia ana :
T_H = 520 + 273 = 793 K
T_L = 110 + 273 = 383 K
Q₁ = 3000 J
I pātaihia :
Q₂ = … ?
Whakautu :
Te whai huatanga o te miihini Carnot:
e = 1 – (383/793) = 1 – 0,48 = 0,52
Whakamahia ēnei raraunga hei tatau i te mahi i mahia e te miihini (W)
(0,52)(3000) = 1560 Joule
Ko te mahi i mahia e te mīhini he 1560 Joules.
Te nui o te wera e tukuna ana e te miihini:
Q₂ = 3000 Joule – 1560 Joule
Q₂ = 1440 Joule
Ko te wera e tukuna ana e te miihini he 1440 Joules.