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Chapter 21: Q. 22 (page 595)

Which, if any, of the heat engines in FIGURE EX 21.22 violate (a) the first law of thermodynamics or (b) the second law of thermodynamics? Explain.

Short Answer

Expert verified

(b) violates first law of thermodynamics .

(a) violates the second law of thermodynamics .

Step by step solution

01

- Introduction (part a)First law of thermodynamics states that energy given to the system must be equal to total energy given out . In other words , energy is always conserved . Second law states that Carnot engine has maximum efficiency . 

Step-2

In (b) total energy input is 500 J and total energy output is 200 J + 200J = 400 J . It violates first law .

Efficiency of Carnot engine = 600-300600脳100=50%

efficiency of (a) = 300500脳100=60%. It is more than 50% , so it violates 2 nd law.

efficiency of (b) = 200500脳100=40%, it is less than 50% , so it does not violate .

efficiency of (c) = 100300脳100=33.33%, it is less than 50% , so it does not violate second law.

02

step 2  Second law of thermodynamics (part b)

Option (a)

Because efficiency has beyond the limiting efficiency, it violates the second rule of thermodynamics.

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Most popular questions from this chapter

The ideal gas in a Carnot engine extracts 1000Jof heat energy during the isothermal expansion at 300掳C. How much heat energy is exhausted during the isothermal compression at50掳C?

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