Entropy chance with a carnot cycle?

AI Thread Summary
In a Carnot cycle, the gas expands adiabatically from 200 degrees to 500 degrees, resulting in an efficiency of 38.8%. During this adiabatic expansion, the entropy change of the gas is questioned. It is clarified that since the process is adiabatic, there is no heat transfer (dQ=0), leading to an entropy change (ΔS) of zero. Therefore, the understanding that the entropy remains constant during adiabatic expansion is correct. The discussion confirms the relationship between adiabatic processes and entropy.
coffeem
Messages
91
Reaction score
0
in a carnot cycle the gas expands adiabatically from 200 degrees to 500 degrees. what is the efficecy? and what is the entropy change of the gas during the expansion?

sorry - i got the efficiency to be: 38.8%

however I am unsure how to work out the entropy chance? any hints?
 
Physics news on Phys.org
however my thinking is that if the the system is adiabatic... then the entropy will stay constant... then it will be 0? am i on the right lines? thanks
 
Hi I am still struggling with this. any advice? thanks
 
coffeem said:
however my thinking is that if the the system is adiabatic... then the entropy will stay constant... then it will be 0? am i on the right lines? thanks

If ΔS=dQ/T and dQ=0 for an adiabatic process then ΔS=0. So you are right.
 
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
View full post »

Similar threads

Efficiency of Stirling Cycle - Is it the same as the Carnot Engine?
Replies
14
Views
1K
Carnot Cycle: Analysis of Energy Exchange
Replies
4
Views
2K
Why Do Different Methods Yield Different Efficiencies in a Reversible Cycle?
Replies
2
Views
2K
How to show that Carnot engine is more efficient?
Replies
1
Views
2K
Is the Use of C_V in Adiabatic Expansion of Carnot Cycle Incorrect?
Replies
7
Views
3K
Entropy of a sealed room with an open-door refrigerator
Replies
5
Views
889
Find the work and heat transferred in a carnot cycle.
Replies
7
Views
4K
Work Done in Carnot Cycle: Adiabatic Compression
Replies
3
Views
2K
Does the Entropy Change in a Carnot Cycle Sum to Zero?
Replies
1
Views
3K
Corrected.Finding the Energy and Work in a Carnot Cycle
Replies
7
Views
2K

Hot Threads

Recent Insights

Back
Top