Recent content by maria clara

Hello, As far as I understand, a transmission line is simply a wave-guide for TEM modes. If the waves are propagating in the z direction so Hz=Ez=0. How does this fact leads to the conclusion that in any transverse plane (xy plane) the fields are conservative? Thanks a lot.

Water and glass are considered denser than vacuum for their dielectric coefficient is greater than the dielectric constant of vacuum. The plasma's dielectric constant is \epsilon0(1-(\omegap/\omega)2) Does this mean that plasma can be considered less dense than vacuum?... thanks in advance.

I'm trying to understand the idea behind the Kronig-Penney model, and its relevance to solid state physics. I understand that the model refers to a particle in a periodic potential. Using Bloch's theorem, and regular boundary conditions the following equation is obtained...

you're right, it doesn't converge. and I just found out that it was all my mistake, it was tanh and not tan... and since tanh is bounded at infinity, tanh(ax)/x definitely approaches zero... sorry guys.. thanks for your help anyway...:)

well, that's exactly the problem, sin and cos don't approach a certain value at infinity, and 1/x does. But is there a theorem that states that if a function approches zero and another function does not approach any specific value, then the product of both would approach zero? I don't think so...

Hi, I've been trying to solve a problem in quantum physics, and got stuck because of a limit. I guess I'm a little rusty on that and would appreciate any help. How can I show that the expression tan(ax)/x tends to zero in the limit x---> infinity? thanks!

OK, so I guess I should just take hbar/\DeltaE as the characteristic time of the system. But what about the difference between the two systems described abouve at tf? Thanks(:

Hi olgranpappy, I copied the question as it is. It isn't the Capital letter I, it's a lowercase "L" - l, the second quantum number. I guess that the "system" is a hydrogen atom, though it isn't explicitly stated in the problem. thanks in advance.

Homework Statement V= V0 (r) + V1(r,t) V0 (r) =-e^2/r V1(r,t) is a small perturbation which is being activated only in the interval 0<t<tf The system starts in the ground state, where l =0 1. If the change in the potential is very slow, what is the probability of finding the system at tf...

thanks but I've never heard of this process, not in our lectures, at least... is there any other way?

Homework Statement A cell diverges into X new cells. Each of them reproduces in the same manner. X is a geometric random variable with success parameter of 0.25. What is the expectation of the number of great-grandsons a cell have? 2. The attempt at a solution I thought about using the...

Hi, Does anybody know where on the web can I find photos of bacteria? I'm searching for co-agulase negative staphylococcus albus and C xerosis. Thanks a lot.

On the Z=0 plane the charge distribution is of the form \rhos=\rho0 sin( \alpha x )sin( \beta y ) find the potential everywhere, assuming that \phi(z\rightarrow±\infty)=0 according to the answer, we should look for a potential of the form A sin( \alpha x )sin( \beta y )f(z) (due to the...

anyone?... please? :blushing:

Hey, thanks again, Ben and gabbagabbahey. Ben, I think you gave me the answer I was looking for, but I still don't fully grasp the matter. I was confused because of the quote I brought in the first message on this thread, where the Green function is described as the mathematical equivalent...