Physics, 21.02.2020 22:23 milkshakegrande101

A metal rod is used to conduct heat between two reservoirs at temperatures Th and Tc, respectively. When an amount of heat Q flows through the rod from the hot to the cold reservoir, what is the net entropy change of the rod, the hot reservoir, the cold reservoir, and the universe? (Use any variable or symbol stated above as necessary.)

Answers: 3

Show answers

Answers

Answer from: shiannethorn

ΔS(rod) = 0 J/K

ΔS(hot) = -Q/T_h

ΔS(cold) = +Q/T_c

ΔS(universe) = -Q/T_h + Q/T_c

Explanation:

We know that an isolated system tends toward disorder and entropy is the measure of this disorder. This means that the entropy of the universe increases in all real processes. And we know that the change in entropy for a system and its surroundings is always positive for an irreversible process like our situation here (in this example). So that, ΔS > 0

ΔS(universe) = ΔS(hot) +ΔS(cold) + ΔS(rod)

Now we need to find the entropy change of the rod. The rod already connected and already in a dynamically steady-state condition and there is no state change occurs in the rod in this thermodynamic processes. Note that the rod absorbs some heat Q from the hot reservoir and at the same time exhausts the same amount of heat to the cold reservoir. This means that the rod is in a dynamic thermal equilibrium and that its temperature will remain constant.

Therefore,

ΔS(rod) = +Q/T(rod) ÷ -Q/T(rod)

ΔS(rod) = 0 J/K (Metal Rod)

Because the temperature of the reservoirs are constant (and we are supposing that the process of losing or adding heat to the metal rod could be reversible in another theoretical experiment), we will use the formula of ΔS = Q/T

Therefore,

ΔS(hot) = -Q/T_h (Hot Reservoir)

Because the hot reservoir is losing heat, we put the negative sign.

ΔS(cold) = +Q/T_c (Cold Reservoir)

Because the cold reservoir is absorbing heat, we put the positive sign.

Because T_h > T_c , so that, I ΔS(hot) I < ΔS(cold) . This means that the decrease of the entropy of the hot reservoir is less than the increase of the entropy of the cold reservoir.

Therefore, the net entropy change of the universe is greater than zero.

ΔS(universe) = ΔS(hot) +ΔS(cold) + ΔS(rod)

ΔS(universe) = ΔS(hot) +ΔS(cold) + 0

ΔS(universe) = -Q/T_h + Q/T_c (which is greater than zero)

A metal rod is used to conduct heat between two reservoirs at temperatures Th and Tc, respectively.

Answer from: Quest

d is the correct answer

An object is located 5.0 cm from a concave mirror. the focal length is 15.0 cm. what is the image di

Answer from: Quest

a lot of it means it can be "burned" for energy and sold at one price. if it is scarce, the price will go up

Another question on Physics

Physics, 22.06.2019 03:00

What are the applications of electromagnetic waves

Answers: 1

Answer

Physics, 22.06.2019 04:00

19. explain why a magnet from your refrigerator could not be used to lift something as heavy as a car. (chapter 7 – pages 202-203) 20. can a magnet ever have a single pole? explain your answer. (chapter 7 – page 208) 21. what happens to the wavelength of a wave if the frequency is increased? (chapter 9 – pages 280-281) 22. an ocean wave has a wavelength of 10 m and a frequency of 4.0 hz. what is the velocity of the wave? show the appropriate equation from your book and show your work with units. (chapter 9 – page 282) 23. as you sit outside, the sound of a siren becomes lower in pitch. is the emergency vehicle moving away from or towards you? explain how you know. (chapter 10 – page 315-316) 24. why are two astronauts in space unable to hear one another? (chapter 10 – page 307) 25. explain in at least 3 sentences how electromagnetic waves form. (chapter 11 – page 338-339) 26. using the chart on page 345 in your textbook, what are the three types of electromagnetic wave with wavelengths shorter than those of visible light. give an example of each. (chapter 11 – pages 345-351) 27. explain why a leaf usually appears to be green, but a rose typically appears red. (chapter 12 – page 373) 28. what is the difference in light that is refracted compared to light that is reflected? think in terms of speed of light as well as what happens to light waves when they interact with a medium. (chapter 12 – pages 369-370) 29. how are concave and convex lenses different? (chapter 13 – page 408-410) 30. what type of mirror is used in rearview mirrors in cars? why is it important that these mirrors have the warning, “objects in mirror are closer than they appear.”? (chapter 13 – page 405)

Answers: 3

Answer

Physics, 22.06.2019 08:30

Pl asaaap ! match the term to the correct description. a type of wave that transfers energy where the particles in the medium move perpendicular to the direction in which the energy is traveling. a type of wave that transfers energy where the particles in the medium move parallel to the direction in which the energy is traveling. movement that is back and forth, like an equal sign = a type of wave that transfers energy where the particles in the medium move in a circle motion while the energy travels left or right. movement that is like a t transfers energy from one location to another 1. wave 2. parallel movement 3. perpendicular movement 4. transverse wave 5. longitudinal wave 6. surface wave

Answers: 1

Answer

Physics, 22.06.2019 16:30

Large electric fields in cell membranes cause ions to move through the cell wall. the field strength in a typical membrane is 1.0 x 10 7 n/c. what is the magnitude of the force on a calcium ion with charge +e? what is its acceleration? is it possible for a particle with the same charge as as calcium to have a different acceleration if placed at this location? what would change the acceleration: mass of the particle? diameter of the particle?

Answers: 2

Answer

You know the right answer?

A metal rod is used to conduct heat between two reservoirs at temperatures Th and Tc, respectively....

Questions