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If this were to be an absolute zero Kelvin, then we could we can have something, T2 Sorry, it's T2.
如果它等于绝对零度，我们可以，对不起，这是。
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So now if I look at my V1 over V2 to the gamma minus 1, that's T2 over T1.
于是把^=中2,的两个温度。
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So, the average is found by taking two instants in time, say t1 and later t2, and you find out where it was at t2 minus where it was at t1 and divide by the time.
平均速度就是取两个时刻,比如t1和之后的t2,用t2时刻的位移,减去t1时刻的位移,再除以这段时间
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RT2 So it's R T2, right, now we're at a lower temperature times log the log of V4 over V3.
等于，这时温度比刚才低,乘以。
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And then there's a cold reservoir T2 at some lower temperature T2.
另外有一个冷的热源,温度为。
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T2 So this is an isotherm at some different temperature T2, a cooler temperature, because this was an expansion.
这个绝热过程的温度是,比T1低，因为这是个膨胀过程。
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So what this says is the efficiency of any reversible engine T1 has to be one minus T2 over T1.
这就是说,任何可逆热机的效率都是,负T2除以。
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p2 So they're both p2. external is p2 p2 V2 T2 and I have p2, V2, T2, on the other side.
都是2,这样末态是。
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So this is just going to be T2 over T1 minus T2, that's our coefficient of performance.
这就是我们的，制冷系数。
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So this is going to end up at T2 a different temperature, we'll call it T2.
这个的末态有不同的温度,我们叫它。
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T2 Is the temperature T2 in this process smaller or larger than if I were to do the process reversibly with the same endpoint pressure.
这里的末态温度,与经过可逆绝热过程,到达相同压强的末态温度相比哪个比较高呢？
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T1 Anyway T2 over T1 is equal to V2 over V3 to the power gamma minus one.
总之，T2除以3,等于V2除以V3的伽马减一次方。
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T2 STUDENT: From T2 reversible is greater than T2 irreversible, saying that T2 reversible is .
学生：可逆过程的,比不可逆过程的T2更高，也就是可逆过程的T2更热。
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T1 So this is negative T2 over T1 over negative one minus T2 over T1.
除以负1减T2除以1,我可以把这些消掉。
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T2 PROFESSOR BAWENDI: T2 irreversible should be colder?
可逆过程的,更冷？
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One plus this, T1 but this is the same as one minus T2 over T1.
加这个，等于1减T2除以。
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So delta u is just equal to the work but we also know what happens T2 because the temperature is changing from T1 to T2.
所以Δu等于输出的功,但我们也知道它会发生,同时我们知道温度从T1变到。
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T2 So we know that delta u is just Cv times T1 minus T2.
u等于Cv乘以T1减去。
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And I compare T2 irreversible T2 They're both less than T1.
我们要比较不可逆过程的,与可逆过程的T2，to，T2，reversible。,显然它们都比T1要小。
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T1 So delta you is just Cv times T2 minus T1.
因此Δu等于Cv乘以T2减。
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As T2 goes to zero, the cold reservoir, then this goes to zero and our efficiency approaches one.
是当T2达到零，也就是低温热源，达到零度的时候,效率可以达到一。
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Here's heat exchanged in pathway A and in pathway B heat is zero, and in pathway C, Cv here is qC it's Cv T1 minus T2.
这是qA，这是路径A上的热量交换,路径B中的热量交换是零，而在路径C中，这是qC，它是。
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/T We've got Cv integral from T1 to T2, dT over T is equal to minus R from V1 to V2 dV over V.
左边是Cv乘以，从T1到T2对dT积分。
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In B it isn't, it's Cv times T2 minus T1, right.
在B中不是，而是Cv乘以。
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V3 Namely, T2 over T1 is equal to V2 over V3.
好，就是T2除以T1等于V2除以。
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UC So we can immediately write delta u C is Cv times T1 minus T2. Delta Hc C is Cp times T1 minus T2, right?
所以我们可以直接写出△,是Cv乘以,△HC是Cp乘以，对吧？
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log We're going to have the ratio of temperatures T1 and the ratio of these logs.
和这些,最后可以得到等于T2除以。
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So that's going to results in an expansion where the new volume new temperature new pressure and an external pressure, p2 which is p2 which is a smaller pressure.
这样经过膨胀,到达了,状态为V2，T2，p2的末态，外界压强也降低到。
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How many people say that T2 irreversible is colder than T2 reversible?
有多少人认为不可逆过程,的T2更低？
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I'm going from T1 to T2, and I have two ways to go here. One is non-adiabatic.One is adiabatic.
从T1升温到T2有两类途径,非绝热，或者绝热。
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