Recent content by Pagan Harpoon

I'm afraid I can't really respond to what you've said about electrical noise, because I don't understand it well enough. In the physics 252 link, the author first considers what the distribution is with respect to height, ignoring velocity. He obtains the exponential dependence. Then, at...

1: Note that at the start of the section entitled "What about potential energy?", in the first sentence where that exponential factor is introduced there is an arrow over the v, indicating that it refers to one specific velocity state. The probability to find a particle in that one state of...

Lots of cases. I mentioned the 1d quantum oscillator, that's one. The most general expression is: P(E) = g(E)*e^(-E/kT) where g is the density of states. So anywhere where the density of states doesn't vary with energy, the distribution would just be the exponential part. Edit - I suspect...

The way I read the passage that you pasted, that's exactly what he's saying. The nuclear reactions create high energy photons, they bounce around and eventually reach the surface of the sun and escape into space. It's important to think about what "bouncing around" means, though. The photons...

There's two things you can do... one is write down the Schrödinger equation and then solve it. The other is to say that the electron's wavefunction has to have nodes at the box edges, so write down an expression for its deBroglie wavelength and apply the appropriate constraints to it.

What is L here? Is the electron in a 3d box and L is the side length? Does the problem say what boundary conditions it wants you to apply at the box edges?

If I were faced with that question, I would calculate the average values for V and K in the classical case (which you have done) and then comment that they are the same as the expectation values in the quantum case - that's how they compare, they're the same. What more do you want to do?

Then haven't you already solved the problem? If you have the expectation values for the kinetic and potential energies in both the classical and quantum cases, then you can compare them and see that they are the same. Is the question asking you for something more?

Is the problem statement telling you that the expectation values for the kinetic and potential energies are each E/2 in the quantum case? If so then perhaps it wants you to calculate the average values in the classical case and show that they're the same.

The number of dimensions is always 3, what I said was that the number of possible directions increases. If I tell you a particle has energy E, then you know that the magnitude of the momentum is |p| = √(2mE). You then know that the vector momentum, (px, py, pz) lies somewhere on the surface of...

When the bullet hits the block, not all of its kinetic energy goes into moving the block. A lot of it will be lost in breaking up the chemical bonds in the wood to embed the bullet in there. The analysis you did assumed that the initial kinetic energy of the block was equal to the kinetic...

I worked in Revenue in Ireland last summer. Almost the whole tax system is now digital. We have an online system for submitting returns called ROS (Revenue Online Service) which is now mandatory for everyone. Paper returns are only accepted from people who have applied for an exemption -...

I agree with the above posters. In some cases, though... people just do it because it's cool. "What's the point of art?" is in a similar vein.

I wouldn't interpret that definition as referring to a proper subset. The part in italics seems to make it pretty clear that it considers every set to be a subset of itself. I don't think the part in bold contradicts that. It says that a subset of S must consist of some of the elements of...

http://oi50.tinypic.com/dyohup.jpg In this diagram, I have tried to illustrate the difference between what happens when gravity is pulling the needle down and what happens when you pull it up with some external force. Fst is surface tension and Fext is whatever external force you use to pull...