Suatu mesin carnot jika reservoir panasnya 400k akan menghasilkan efisiensi 40c, jika reservoir panasnya bersuhu 640k berapakah efisiensinya?

TERMODINAMIKA

T1 = 400 K. η. = 0,4
T1' = 640 K. η' = __?

efisiensi
η = 1 - T2 / T1

keadaan pertama
0,4 = 1 - T2 / 400
T2 / 400 = 0,6
T2 = 240 K

keadaan kedua
η' = 1 - 240 / 640
η' = 1 - 3/8
η' = ⅝ = 62,5 % ← jwb

Diket :
T1 = 400 K ==> η = 40%
T1' = 640 K ==> η' = __?

Jawab :
Step 1
---------
η = 1 - (T2/T1)
(T2 / T1) = 1 - η
T2 = (1 - η)•T1

Step 2
----------
Karena Suhu rendah tetap maka :
T2 = T2'
(1 - η)•T1 = (1 - η')•T1'

Maka :
(1 - η') = (T1 / T1')•(1 - η)

η' = 1 - [(T1 / T1')•(1 - η)]

η' = 1 - [(400 / 640)•(1 - 40%)]

η' = 1 - [(5/8)•(1 - 0,4)]

η' = 1 - [(5/8)•(0,6)]

η' = 1 - [3/8]

η' = 5/8

η' = 62,5%

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