Recent content by T-7

I think Anony. is under the impression that, being part of a set Q, this isn't up for discussion. According to the tutor I asked, we *can* discuss these Qs with other Physicists, exchange ideas, argue, etc. What we're not allowed to do is just copy someone's answer (which PhysicsForums also...

Hello folks, I could really do with a few hints with this. (As soon as possible!) Homework Statement For a repeated line of cells, two 'equations of motion' can be written: C_{n}\dot{U_{n+1}} = I_{n}-I_{n+1} L_{n}\dot{I_{n}} = U_{n} - U_{n+1} where C_{n} is the capacitance, U_{n+1} the...

Whilst we are intended to work through the exercises ourselves, as far as I know we're encouraged to discuss all the problems, and the lecturer has been willing to take questions himself on any of the set problems. I've not reproduced my working in detail here for anyone to copy, nor am I asking...

Hi, Here's the problem: Homework Statement Quantum particle moving in 1D. Potential energy function is V(x) = C|x|^{3}. Using the variational method, find an approx. ground-state wave function for the particle. The Attempt at a Solution Using \psi = Ae^{-ax^{2}}, I find that A =...

Hi, I'd really appreciate some speedy advice on this question. I need to know whether the expressions for energy and the angular momentum are correct, as I seem unable to produce the final expression desired from what I have derived. Here's the problem: Homework Statement The Lagrangian is...

Homework Statement I am after an expression for the time T it takes to slide down from height zero to -h of the brachistochrone. (Starts from x=y=0, slides along a distance -x, descends a height -h). Homework Equations I have deduced that T = \frac{1}{(2g)^{1/2}} \int _{0}^{-h}...

Thanks for your thoughts folks. Much appreciated. :-)

Hi, I have done the integral on paper and on Maple. On Maple I put: > value( Doubleint( (2/a)*sin(Pi*x/a)*sin(2*Pi*y/a)*(x^2+y^2)*(2/a)*sin(2*Pi*x/a)*sin(Pi*y/a) ,x=0...a,y=0...a) ); The (x^2+y^2) is there, as you can see. The result is zero (which is what I also get using paper and...

Hello, This is a question on perturbation theory - which I am trying to apply to the following example. Homework Statement The two-dimensional infinitely deep square well (with sides at x=0,a; y=0,a) is perturbed by the potential V(x)=\alpha(x^{2}+y^{2}). What is the first-order correction...

Yep. :-)

Hi, I'm stuck on what I suspect is a really easy proof. I'd appreciate some rapid help! Homework Statement For a trajectory with given initial position and velocity, we can always rotate the system of coordinates such that initially d\theta / dt = 0 and \theta= \pi/2 say, t = 0. Using the...

I'm wondering -- would you get the phenom. of Bose-Einstein condensation in a 2D system. My intuition is "no", but I'm having a hard time saying why. I suppose I could try and work it out mathematically (no time, right now) -- perhaps someone has? -- but a physical explanation would be nice too...

Thanks for your reply :-) I believe we are supposed to use a density function, however -- at least, it says later in the question to show that F \approx NkT log \left(\frac{AkT}{Nh^{3}mg}(2\pi mkT)^{3/2}\right) h is Plank's constant. This *looks* to me like an expression has been derived for...

Partition function for a gas in a cylinder -- urgent! Hi, Here's the problem -- it's supposed to be a specimen of what I can expect in my exam, but it isn't much like the tutorial questions I've been doing. I'd really appreciate some help -- fast! Homework Statement An ideal gas consisting...

Of course. I just wasn't handling the log properly when I differentiated it (!). Cheers.