Recent content by kiwakwok

In the foreword of the new edition of the book: "Feynman delivered 27 lectures in all, one each week over the full 1962–63 academic year. The class met ... Only 16 lectures are included in this book; these correspond, roughly, to the first 16 of the 27 that Feynman gave. Morinigo and Wagner...

The Feynman Lectures on Gravitation is a famous book. There are originally 27 lectures but only the first 16 has been published. The remaining 11 lectures can only be found in the first edition (1962-63). It is very rare but is there a (possible) way to read the content, provided that my...

I was reading Griffiths's book on quantum mechanics. In chapter 6, he tried to derive the spin-orbit coupling using a classical approach. H=-\vec{\mu}\cdot \vec{B} 1. Finding the relation between \vec{μ} and \vec{S} He consider a spinning charged ring with mass m, radius r, total charge...

Do you mean? \frac{\lambda(t)}{a(t)/a(t_L)}=\lambda (t_L) d\nu=-\frac{1}{\lambda^2}d\lambda=-\left(\frac{a(t)}{a(t_L)}\right)^2\cdot\frac{1}{ \lambda (t)^2}d \lambda

I would like to ask one more question: --Quote-- As time pass, the matter became cooler and less dense, and eventually the radiation began a free expansion, but its spectrum has kept the same form. We can see this most easily under an extreme assumption, that there was a time t_L when radiation...

I was reading Weinberg's book Cosmology. When I went to chapter 2, under the subsection 2.1 "Expectations and discovery of the microwave background" I could not understand one statement. ---Quote--- The work done by pressure in an expanding fluid uses heat energy drawn from the fluid. The...

I am reading Jackson's electrodynamics book. When I went through the Legendre polynomial, I have a question. In the book, it stated that from the Rodrigues' formula we have Consider only the odd terms...

dextercioby and tom.stoer, thanks very much.

Nice. Thanks.

I read few pages of the book by Fonda and simply ensure that I am really understand. Quote: --- --- --- --- --- Wigner's Theorem Suppose that we have chosen a particular one-to-one vector mapping T compatible with \mathbf{T}, of the coherent subspace \mathcal{H}_c onto the coherent...

I was just interested in such a stupid question xP

I guess you have some basic knowledge in algebra, geometry, pre-calculus and calculus. I suggest the very first topic is SI unit system, and densional analysis. Then, you may start to work with Newtonian mechanics. By the way, if you are green in physics, you may start with some...

Thanks tiny-tim. I have one follow-up question: In spherical coordinate, we can clearly see that the integral above will not blow up even at the singularity. The situation should be the same no matter which coordinate system we use. In the Cartesian coordinates, the integral can be rewritten as...

I am reading a quantum mechanics book. I did not clearly understand one particular idea. When the book talks about the time-evolution operator U(t,t_0), it says that one very important property is the unitary requirement for U(t,t_0) that follows from probability conservation. My question is...

I am currently reading a book about the electromegnetism. When I went through the introductory chapter, there is a small part that I do not understand clearly. Therefore, I hope that I can seek help here. Quote: --- --- --- --- ---...