# Broglie wavelength

1. Aug 2, 2008

### glueball8

Helium becomes a super°uid at temperatures T <
2:18 K. A super°uid °ows with no viscosity. This behaviour
can only be explained using quantum physics and it can
only happen if the de Broglie wavelength of a helium atom,
of mass m, is comparable to the inter-atomic spacing of the
°uid. What could be an expression for
the de Broglie wavelength?

Can anyone tell me where to learn this?

I'm currently working on Fundamentals of Physics, would I understand this when I finish the book? What level is this?

2. Aug 2, 2008

### G01

The debroglie wavelength is a concept in modern/ quantum physics. If you have an edition of Fundamentals that includes a section on modern physics, then the book should cover the DeBroglie wavelength.

In short, the Debroglie wavelength expresses the wave-particle nature of matter by assigning a wavelength to matter particles. A particle's deBroglie wavelength is given by:

$$\lambda_{deBroglie} = \frac{h}{p}$$

where p is the particle's momentum, and h is Planck's constant.

Also, for an introductory summary of the topic:

http://hyperphysics.phy-astr.gsu.edu/Hbase/debrog.html

3. Aug 3, 2008

### cesiumfrog

I hadn't thought of super-fluids in that way..

The OP may also want to google for thermal velocity distributions (and Bose-Einstein statistics).

4. Aug 3, 2008

### glueball8

oh I know that equation and stuff but I can't get an answer. Its a mutiple choice and I think the (A) Based on it looks like the mv is just changed {answers shown below on the pic I think}.

Is K a constant?

Last edited: Mar 5, 2009