Griffiths Definition and 230 Threads

Homework Statement Confirm that the retarded potentials satisfy the Lorentz gauge condition. Homework Equations \vec{A}(\vec{r}, t) = \frac{\mu_{0}}{4\pi}\int\frac{\vec{J}(\vec{r'},t_{r})}{R}d\tau' V(\vec{r}, t) = \frac{1}{4\pi\epsilon_{0}}\int\frac{\rho(\vec{r'},t_{r})}{R}d\tau' Where...

Zero field magnetisation like a function of temperature vanished in ##T=T_c## as ##(T_c-T)^{\beta}##. Let ##M_1## be a magnetisation for temperature ##T_1##. Since ##\forall M<M_1##, ##(\frac{\partial A}{\partial M})_T=H=0## it follows that A(T_1,M)=A(T_1,0) for ##M \leq M_1(T_1)## Why only for...

I have the option of doing either a one-semester QM course with Griffiths or a two-semester course with Shankar. Background is Eisberg and Resnick's "Quantum Physics". I really like quantum mechanics and would rather do two semesters, but will Shankar be too formal for an upper-level undergraduate?

Homework Statement A spherical shell of radius R carries surface charge density \sigma=k \cos \theta. Whats the dipole moment of this distribution?Homework Equations The dipole moment is calculated as \bf{p} = \int \bf{r}' \sigma (\bf{r}') d\bf{a}' (Griffiths, Eq. 3.98).The Attempt at a...

Hi, I'm reading the section about "How the fields transform" in Griffiths' Intro to Electrodynamics book, but I'm a little confused and want to understand this fully. He starts off with the example of a parallel plate capacitor where each plate has charge density \sigma _0. So in the rest...

I've seen quite a few people on this forum agree that Griffiths is not a good book to learn QM from. But I was wondering what reasons people would give for it. (Personally I don't feel I can give an in depth critique since I've only sampled his book. I rather liked his explanation of...

This summer I plan to self study quite a bit and want to learn as much as I can. I'm an EE major and have taken Calc 1-3, and DiffyQ/Linear algebra as well as intro physics classes. I will be taking classical mechanics in Spring 2013 but wanted to dive into Griffiths E&M book this summer. Is...

Homework Statement It's example 3.8 in the Griffiths book in case someone has it. Basically the problem involves a uncharged metal sphere in a uniform field in the +z direction. Naturally, there will be induced positive charges on top and negative charges at the bottom. The question asks for...

Hello, I'm taking a particle physics class and we're using Griffiths' book "Introduction to Elementary Particles". I was reading in it but two statements in it (on the same page, for reference p33 in the second edition) struck me as weird, and as I would greatly appreciate if anyone could...

Hi, I am Liu, a undergraduate in mainland China, I post out this idea and want to see how you gentleman think, here it is: Griffiths says, in his book < Introduction to Quantum Mechanics >, if an insect fly in a path perpendicular to the direction in which lightbeam goes, the velocity of...

In the prove of the Schrodinger equation preserves the normalization I don't understand the step from ∂ψ/∂t=ih/2m ∂2ψ/∂x2- i/h Vψ to ∂ψ*/∂t=-ih/2m ∂2ψ/∂x2+ i/h Vψ* (h represents h bar) the book says "taking complex conjugate equation" but I don't see how. Thanks in advance.

I was wondering whether I should brush up on ode's/pde's or just go through the math appendix of Griffiths to prepare myself. How much ode's/pde's is needed for Griffiths and Ryden? Thanks

Hi all I am trying to go through the Griffiths Intro to QM book and I'm afraid I'm already stumped! He determines the momentum operator by beginning with the following equation: <x>=\int_{-\infty}^\infty {x|\psi(x)|^2} He takes the time derivative and manipulates the integral: (I'm...

So I'll be taking undegrad E&M 1 next semester and was looking for a good book to prepare for it before the semester starts. People seem to like Griffiths and Purcell generally. Shwartz also seems to have some good reviews (and is quite cheap) on Amazon but I'm not quite sure what level it is...

I need to self-teach myself electromagnetism, and both of these books have been recommended to me. Essentials of Electromagnetism, by Dugdale https://www.amazon.com/dp/B000PY3WG0/?tag=pfamazon01-20 Introduction to Electrodynamics, by Griffiiths...

Find the expectation value of the potential energy in the nth state of the harmonic oscillator. This is his example 2.5 in the book, he uses a\pm=1/Sqrt[2hmw](\mpip+mwx) to get x=Sqrt[h/2mw](a_{+}+a_{-}) My question how does he do this? I can't seem to make the algebraic manipulations to...

Hello everyone, and thanks for reading. I'm having a difficult time understanding something. On yet another attempt to deepen my quantum mechanics understanding I referred to the widely recommended book of Griffiths. I find the book indeed very good and pretty thorough in it's scope. There...

I would just like to start off by saying the problem comes from Intro to electrodynamics, 3rd edition, griffiths. the problem is number 1.9. Question: Find the transformation matrix R that descries a rotation by 120 degrees about an axis from the origin through the point (1,1,1) the...

Calculate d<p>/dt Answer: d<p>/dt = <-dV/dx> generally speaking (I believe) you need to use scrodinger's equation (both of dphi/dt and dphi*/dt) and the expectation value of momentum: <p> = -i*h_bar * integral (phi* * dphi/dx) dx. I would say that the way I used Cramster was just short of...

Homework Statement If x is the position of a particle then the expectation value of x, <x> is : (I got lazy and just copied an image from Wiki, just pretend <x> is on the lhs of the eqn) When Griffith derives an expression for d<x> / dt, he uses the fact that dx/dt is zero, since "the wave...

Homework Statement Folks, I am looking at a past exam question regarding the Harmonic Oscillator. The question ask 'Justify that the ground state of a harmonic oscillator a_\psi_0=0 equation 2.58 on page 45 of griffiths. THis was not covered in my notes. Any ideas how to justify this...

In Griffiths book (Intro to Electrodynamics, page 489) he uses one simple gedanken experiment with train, lamp and mirror, to prove the length contraction \Delta x'=\gamma \Delta x. My question is why he uses two directions of light and not just only one? For example, when we use, for observer...

I am a self studyer and I studied "Field and Wave Electromagnetics" by David K Cheng and "Introduction to Electrodynamics" by david Griffiths. Cheng is more for EE where it put a lot of effort in phasor, transmission lines, Smith Chart. Griffiths is more on the physics side that cover in more...

Hi everyone I'm a math student trying to go through Griffiths Harris Principles of algebraic geometry. I'm especially interested in complex tori and K3 surfaces but I confess I'm having a hard time. Can anyone suggest a reference (online notes or books, preferably a single book) that covers the...

I will refer to Griffiths' textbook Introduction to Electrodynamics, Third Edition. On page 70 he calculates divergence of E and implicitely assumes that divergence of rho is 0, where rho is charge density distribution. On page 223 he calculates rotB and says that rotJ = 0, where J is current...

The is example 10.1 in page 417. The example is the find the current density from given condition: V=0,\;\;\hbox{ and } \;\;\vec A=\frac{\mu_0 k}{4c}(ct-|x|)^2 \hat z \;\hbox { for x = +ve and }\;\; \vec A=0 \;\;\hbox { for x = -ve.} c=\frac 1 {\sqrt{\mu_0 \epsilon_0}} From this...

I just read in Griffiths 'Electrodynamics' (chapter 12.3) how magnetism is a relativistic phenomenom, why there had to be a thing like magnetism just given electrostatics and relativity. Is the same true for the weak force and the strong force? Is there also magnetism? If so, how is it...

In Griffiths Intro to QM (2nd edn) p437 -on linear independent vectors.. " A collection of vectors is said to span the space if every vector can be written as a linear combination of the members of this set". Well, does this means all member vectors are linearly dependent because that's what...

I have a few question on the derivation of the Fresnel's equation in Griffiths' book P389. This is the diagrams representing the parallel polarization. The plane of incidence is the xz plane at y=0. boundary is the xy plane. \vec{k_I},\; \vec{k_R},\;\vec{k_T} are direction of incidence...

I am confused with this part of "Introduction to Electrodynamics" 3rd edition by Dave Griffiths. On page 367, the traveling wave is represented by: f(z,t)\;=\; A cos[k(z-vt) \;+\; \delta] 9.7 Where v is velocity and kv=\omega. This give: f(z,t)\;=\; A cos[kz \;-\;\omega t \;+\...

We just started the course on Quantum Mechanics and this is the 'official' textbook we're using. I have heard many people speak fondly of this book and so far I do like that the author writes in a colloquial style. However, reading it, I feel dumb. Schrodingers equation is just thrown out there...

I Uwould be grateful if anybody can kindly help me with this particular doubt that cropped when I was working through Introduction to Quantum Mchanics by Griffiths ( Griffiths page 66 ) My question is how is the following obtained : aj = C / (J/2)! ( Please read j as subscript of...

I'm taking junior level E&M this semester and we are using Foundations of Electromagnetic Theory by Reitz. I have previewed the book and it seems a little on the less thorough side while also requiring much prior knowledge of the subject. Are there any other texts which I could supplement with...

Since I'm reading SR/GR now, I thought I'd complement it with a treatment of EM also. I am looking for a treatment of electrodynamics at the level of Landau, i.e. I want the covariant formulation and the Lagrangian formulation of the fields. My background is the level of Griffiths. Landau seems...

sorry about my English Homework Statement In Purcell 3.7 (Problem) and Griffith there is a question,look at fig. (we have 4 conductors with charges +Q,-Q,+Q,-Q (b),what will happen if we connect them with tiny wires in pairs ) Griffith say that c distribution of charge ,can't be a...

Homework Statement A surface at z = 0 is held at potential V (x, y) = V0 cos(qx) sin(qy). Find the potential in the region z > 0. Homework Equations Laplace's equation in Cartesian coordinates The Attempt at a Solution I wrote at least a page of my past 2 attempts at a solution...

Hello, Well, actually it's not a homework problem, I just got really confused about bound charges. Originally, I thought it was just a special technique to do the integral, but somehow Griffiths suggest that bound charges are phsically exist.(chap. 4.2.2) Well, I can accept his argument...

Golden Rule for Decays in Griffiths' "Introduction to Elementary Particles"? Hello, I'm getting a bit bogged down in constant factors while reading Griffiths' "Introduction to Elementary Particles", 1st edition. In particular, I'm having problems with equation 6.15: d\Gamma =...

Homework Statement This isn't really a homework question, but something I've been wanting to know out of curiosity in David Griffiths' Introduction to Electrodynamics. On pages 131 and 132, there is a Fourier series, V(x,y) = \frac{4V_0}{\pi}\sum_{n=1,3,5...}\frac{1}{n}e^{\frac{-n \pi...

Justification of ψ*ψdx as probability density of particle between x and x+dx using light's E-field and diffraction by slit. This isn't a homework problem, rather it was on the list of things to know for the exam. They don't really go over it in Griffiths Quantum Mechanics books. So are any...

After deriving the self energy, or the energy to construct a charge configuration\frac{\int_{V} \epsilon E^{2}dV} {2} (where V is the volume over which the E-field of the configuration extends.) Griffiths goes on to say that the energy required to construct a point charge using the above...

Homework Statement Show that the electric field of a "pure" dipole can be written in the coordinate-free form E_{dip}(r)=\frac{1}{4\pi\epsilon_0}\frac{1}{r^3}[3(\vec p\cdot \hat r)\hat r-\vec p]. Homework Equations Starting from E_{dip}(r)=\frac{p}{4\pi\epsilon_0r^3}(2\cos \hat r+\sin\theta...

Consider double finite square well with -Vo; -(a+b/2) < x < -b/2 V(x) = 0; -b/2 < x < b/2 -Vo; b/2 < x < a + b/2 0; otherwise Sketch the ground wave function Psi(n=1) and the first excited state Psi(n=2) for 1. b = 0 2. b~a 3. b >> a So...

Homework Statement Hi, The problems asks to calculate multiple things for a Gaussian wave packet. Steady state function: psi(x,0)=A*exp(-ax^2).My problem is that I'm stuck at calculating <p^2>.Homework Equations <p^2>=Int(|psi|^2*(-1*h^2*d^2/dx^2))dx or...

I'll explain the problem. \cdots \cdots \cdots \cdots \cdots \cdots \ldots=====|====== \cdots \cdots || LOOP | LOOP || --> V \cdots \cdots ||=====|=====|| \cdots \cdots <-x-> ..| \cdots \cdots [Dotted area indicates field] In the usual discussion of motional emf, all...

This is not actually a homework question, just something I am wondering about. A specified charge density dependent on /theta is glued over the surface of a spherical shell and you are asked to find the potential inside and outside the sphere, which is done in the example using separation of...

I'm trying to read through Griffiths' QM book, and right now I'm on the series solution to the harmonic oscillator (ch 2). I'm having a hard time following the math (especially after equation 2.81) in this section, so if anyone has read this book, please help. My first question is about the...

"Life" after Griffiths EM Hi, I need a textbook on electrodynamics. I have already finished Griffiths electrodynamics, a wonderful book but it does not cover the things I need now from an EM book (i.e. research on photonics). Therefore, I need a book which covers the mathematical methods...

It has been awhile since my multivariable calculus course. I do not want to review everything before tackling these texts, just the important stuff. What concepts and theorems are most important? Anything from linear algebra I should review? Thanks.

Hi, could anyone please tell me equations 6.34 and 6.31 from Griffiths elementary particles book ( the new edition)? I need to do problem 6.5, I have the old book, and I can't make any connection. Can't find the new book either right now, and I need to do it by tomorrow.. Please help, i'd...