Recent content by Livethefire

I've been looking for a condensed matter problem book (undergrad to graduate level) to brush up on a lot of things. I have Kittel and Ashcroft & Mermin but was looking for something more along the lines of 'A Guide to Physics Problems' to get right to the heart of problem solving. I see...

The student had something more like this: The Upper "V" was positive, and the lower was negative. In otherwords half the rod was positive, the other was negative. This allowed the repulsion to still be correct.

Hey, I am helping out with a class and the students were given a question about an electroscope that is being charged by induction, and they have to label the charge distribution on a diagram. The diagram is drawn such that the conductive elements are separated - indicating a force between...

I realize this might be a complicated question, but I can't seem to find any textbooks or papers that address this head on. Perhaps I am naive in this field. What happens to the electric and magnetic parts of a radio wave as it passes through the human body? As far as I understand: The...

What I was saying in post #1 was to sub iy for y in the first equation you get the second. In other words, rotating the axis 90 degrees changes the view from a circle to a hyperbola. Sometimes i is used as a 90 degree operator, yet I think my reasoning is unsound, thus i am asking here for...

Ah yes! But is there any relevance or justified motivation to present such a thing by substituting "iy" in a circular equation?

Forgive the sloppy use of math and inability to produce an image. I noticed this last christmas. If you have a fairy light ( or perhaps any LED etc), and shine it normal to a surface, you see a circle. If you place the light flat on the surface you see a curve - to me the fairy lights' curve...

Thanks, Yeah I got it working. There are curly brackets around my numerical results though : Output: {100.00} Anyway to get rid of them?

I am kind of new to mathematica, and have checked the documentation but can't seem to find an answer. I have solved 3 coupled differential equations using NDSolve. I wish to integrate the solutions over a range but I'm not sure how to do it - the documentation seems to deal only with...

One standard result is from: http://en.wikipedia.org/wiki/Integral_of_a_Gaussian_function" yielding \frac{\sqrt \pi }{\sqrt \epsilon } \exp \left ( \frac{-k^2}{4\epsilon} \right )

Wow that was bad maths in #5. I just woke up and saw it was clearly wrong - must have been tired. Is there any "clear" way to explain why that methodology doesn't work other than: differentiating the result is a quotient (ultimately due to the fact the function isn't linear) and thus more terms...

The limits on the integral are surely -infinity to infinity for all space, but that poses problems also. Regardless, indefinite : \int e^{i(k-k')r-\epsilon r^2} dr \lim_{\substack{\epsilon \rightarrow 0}} \frac{e^{i(k-k')r-\epsilon r^2}}{i(k-k')-2\epsilon r} + C...

To be clear, is this what you mean? https://www.amazon.com/dp/0120598256/?tag=pfamazon01-20 I must go check my mathematics text... Thanks a lot! Ill check that out in the library tomorrow

Simple Integral: Complex exp --> delta function My Professor has written this down but I'm having some trouble of precisely where this is coming from: \int\psi^*_{f}(\boldsymbol k')\psi_{f}(\boldsymbol k) d^3\boldsymbol r = (2\pi)^3\delta(\boldsymbol k- \boldsymbol k') where \psi_{f} =...

Background Next year I am going to be a final year student - Msci Physics. I am fairly mathematically competent even though I don't "take" any theoretical/math options (my confidence in this area is another question). In first year we had a standard introduction to all the topics we were...