What happens at the lambda point of superfluid Helium?

In summary, the conversation discussed the solution to a homework problem involving rearranging equations and using the relationship for relative velocity. The conclusion was that at the Lambda point, there is a discontinuity in heat capacity that causes the ratio of Vs/Vn to become infinitely small, resulting in the velocity of the superfluid becoming infinite to maintain zero mass flux. The problem was ultimately solved.
  • #1
CMJ96
50
0

Homework Statement


mdxsuIt.png

2. Homework Equations are given in the above picture
3. The attempt at the solution

In part a) I simply rearranged the other expressions given and subbed them into the relationship for relative velocity and came out with Vns= Qdot/ρsT(1- ρn/ρs).Then in part b) I started by rearranging the equation for Qdot to get an equation for Vn and subbed T=0 in, this then allowed me to come to the conclusion that Vn must blow up to infinity if T -> 0 and hence Vs/Vn will become 0.
However, I have a problem with the second part of b), I have been thinking about it and understand that at the Lambda point there is a discontinuity in the heat capacity and hence it will blow up to infinity too, here is where my problem arises, I'm not sure how that effects the ratio of Vs/Vn, my idea was that if the heat capacity is infinite the helium will simply absorb all of the heat and will store it as internet energy, hence it will not move away from the heat source? Any guidance would be greatly appreciated
 
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  • #2
I've figured this out, turns out the ratio of superfluid falls to such an infinitely small number that the velocity of the superfluid would tend to infinity to maintain zero mass flux, so I will mark this as solved
 

Related to What happens at the lambda point of superfluid Helium?

1. What is the lambda point of superfluid Helium?

The lambda point is the temperature at which superfluid Helium undergoes a phase transition from a normal liquid state to a superfluid state.

2. How is the lambda point of superfluid Helium measured?

The lambda point can be measured using various techniques, such as calorimetry, sound velocity measurements, and NMR spectroscopy. These methods involve monitoring changes in physical properties of the Helium as it approaches the lambda point temperature.

3. What happens to the viscosity of superfluid Helium at the lambda point?

At the lambda point, the viscosity of superfluid Helium drops to almost zero, allowing it to flow without any resistance. This is one of the defining characteristics of superfluidity.

4. How does the lambda point of superfluid Helium compare to other phase transitions?

The lambda point is one of the lowest known phase transition temperatures, occurring at around 2.17 Kelvin (-270.98 degrees Celsius). This is lower than the boiling point of Helium, which is around 4.2 Kelvin.

5. What is the significance of the lambda point in superfluid Helium research?

The lambda point is of great interest to scientists as it marks the transition to a state of matter with unique properties, such as zero viscosity and the ability to flow through extremely small spaces without resistance. It also has applications in cryogenics and quantum physics research.

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