• Support PF! Buy your school textbooks, materials and every day products Here!

Second law of thermodynamics

  • Thread starter cowcow8866
  • Start date
  • #1
11
0

Homework Statement



In the tropics, the water near the surface is warmer than the deep water. Would an engine operates between these two surfaces violates the second law? Why?

Homework Equations


Clausius statement:
Heat generally cannot flow spontaneously from a material at lower temperature to a material at higher temperature.

The Attempt at a Solution


I only knoe that the water near the surface is a high temperature reservoir and the deep water is a low temperature reservoir. Any engine only absorb heat at high temperature reservoir and do work and rejects heat at low temperature reservoir. I don't know what is the relationship of this with the second law. Thank you.
 

Answers and Replies

  • #2
dlgoff
Science Advisor
Gold Member
3,814
1,741
I don't know what is the relationship of this with the second law.
http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html" [Broken]
 
Last edited by a moderator:
  • #3
11
0
http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html" [Broken]
YES,.........
But anybody can give me some hints or direction to tackle this question?
 
Last edited by a moderator:
  • #4
dlgoff
Science Advisor
Gold Member
3,814
1,741
Note that from the mathematical definition of entropy, a process in which heat flows from cold to hot has decreasing entropy. This can happen in a non-isolated system if entropy is created elsewhere, such that the total entropy is constant or increasing, as required by the second law.
http://en.wikipedia.org/wiki/Second_law_of_thermodynamics" [Broken]
 
Last edited by a moderator:
  • #5
Andrew Mason
Science Advisor
Homework Helper
7,586
346

Homework Statement



In the tropics, the water near the surface is warmer than the deep water. Would an engine operates between these two surfaces violates the second law? Why?

Homework Equations


Clausius statement:
Heat generally cannot flow spontaneously from a material at lower temperature to a material at higher temperature.

The Attempt at a Solution


I only knoe that the water near the surface is a high temperature reservoir and the deep water is a low temperature reservoir. Any engine only absorb heat at high temperature reservoir and do work and rejects heat at low temperature reservoir. I don't know what is the relationship of this with the second law. Thank you.
The answer is no. So long as heat flows from the warmer reservoir to the colder, there is no violation of the second law.

AM
 
  • #6
I have had a simple question that has nagged me since my '60s era physics classes. Simply put, does an an atom's energy "run down" over time? e.g. Is it a constant or does it drop over time due to entropy? If it drops over time, what is the lifetime of an atom?
 

Related Threads on Second law of thermodynamics

  • Last Post
Replies
4
Views
4K
  • Last Post
Replies
1
Views
3K
  • Last Post
Replies
1
Views
627
  • Last Post
Replies
1
Views
1K
Replies
2
Views
6K
Replies
1
Views
1K
Replies
1
Views
3K
Replies
3
Views
9K
Replies
1
Views
2K
Replies
13
Views
413
Top