Griffiths Definition and 227 Threads

In the (b),I have some questions: (1) Does it mean ψ can be real or not real? (2) Why do the solutions of linear combination must have the same energy? As I know, these solutions are often different, as long as they are eigenvalues of time-independent Schrodinger equation. (3) In the sentence...

Hey SIr , (Addressed to Sir J D Grififfiths) Last year when I took basic electricity and magnetism course , my instructor discussed some interesting ideas which you discussed in your book ''Introduction to Electrodynamics'' ,one of that was calculating force exerted on a dielectric while it's...

I can't understand the solution to Problem 1.4(a). The solution is the following: What puzzles me is that ρ(θ)dθ=ρ(x)dx ? Why are they equal?

TheAdmin submitted a new PF Insights post Interview with a Physicist: David J. Griffiths Continue reading the Original PF Insights Post.

Hi all, "Integral can be done by partial fractions - or look it up" So second line, that's what I want to do. How to deal with this? What substitution can I use? Never encountered partial fractions with non-integer exponents. Someone give me a tip? Thanks in advance

I heard that Griffith's Electrodynamics is at a similar level of Purcell's book on electricity; is it fine if someone goes into a graduate level electrodynamics book right after Purcell?

In Griffiths intro to quantum mechanics, there are a few things that I feel like he gets from nowhere, he just states it and doesn't derive it or prove it. First is equation 3.114, using opperators to get the expectation value of an observable. I get how he got the inner product from the...

Homework Statement We want to calculate the field of a uniformly polarized sphere of radius=R Homework Equations V(\vec{r}) = \frac{1}{4 \pi\epsilon_{0}} \oint_{S} \frac{\sigma_{b}}{r} da' + \int_{V} \frac{\rho_{b}}{r} d\tau' The Attempt at a Solution i)I know that \sigma_{b} = P...

I want to study quantum mechanics for undergrad level, and found out really lots of people recommends "Introduction to Quantum Mechanics by David J.Griffiths" which is Alright, so I visited my school book store for this cat-pictured book. and found this puzzle-pictured book. Same name same...

What does this formula measure? c= \sqrt{2EY/\pi} This topic is from fracture mechanics. Does this formula tell you how much stress is required to cause the crack to increase?

Homework Statement I am trying to solve Problem 2.45 in Electrodynamics by Griffiths, however, my answers were different from those in the book, I am suspect I got a missing step but I could not find it, so here is the Given Problem Find the charge density \rho given by a potential...

Whole my life I have been interested in Quantum Physics. I have a bachelor degree in IT. I did not finish my studies. I have always been quite sloppy in studying in school. As a result, my mathematics skills are terrible. I often get pointed out on this forum that I better start with the...

In Grifftiths Intro to Quantum 2nd edition, page 51, he is re-expressing the Schrodinger equation for a harmonic oscillator in terms of a unit-less quantity \xi \equiv \sqrt{\frac{m\omega}{\hbar}}x So Griffiths takes the Schrodinger equation in equation [2.70] -\frac{\hbar^2}{2m}...

Hi, I am a math major, currently in my 3rd year of undergraduate studies, majoring in measure theory / probability / mathematical statistics. I am in the dubious situation that I will be taking a course on QM while having so far only studied classical mechanics (i.e. all chapters on classical...

I really like the book, its the first physics textbook that I liked actually. But I've found a minor error. On page 8 (chapter 1 The Wave Function) it says that if you sum deviations from average of a random variable you'd get zero because " Δj is as often negative as positive", here's the...

Well, I am a bit confused. Griffiths himself writes in his book "Introduction to Electrodynamics" at one point in his book that this law is "simply wrong". In a footnote, he writes that it was wrong in principle wheras it is true for non-relativistic speeds, and later on in his book, he goes on...

hello all Prior to my studies in QM I would need a brief intro to quantum physics. I know there are lot of books on modern physics that cover these topics, but really like Griffiths' style, and my QM textbook is precisely his QM book. So, my question is if "revolutions in 20th century physics"...

What math should a person know to THOROUGHLY understand everything in this textbook(Introduction to Quantum Mechanics by David Griffiths)? (For refrence) cal2 cal3 diffeq1(ode) diffeq2(pde) linealg vectorcalc realanal1 realanal2 Please list all you think are necessary. Thanks

Homework Statement Starting from E^1_{fs} = \left<n l m_l m_s| (H_r + H_{so})| n l m_l m_s \right> and using E_r^1 = -\frac{(E_n)^2}{2mc^2}\left[\frac{4n}{l+1/2} - 3\right] and H_{so} = \frac{e^2}{8\pi\epsilon_0}\frac{S\cdot L}{m^2c^2r^3} and \left<\frac{1}{r^3}\right> =...

Homework Statement ##\int_0^\pi \sin^{2l+1}\theta~d\theta## Homework EquationsThe Attempt at a Solution I have no idea how to proceed with integrals of this type, and I can't find any similar examples online. If someone could give me some info on these types of integral, or direct me towards...

1. In the part of the analytical solution of the harmonic oscillator, p38 in my version of the book a certain mathematical trick is used. The position part of the wave function in function of a dimensionless variable z, is given by ##\frac{d^{2}\Psi(z)}{dz^{2}}=(z^{2}-K) \Psi## In the limit of...

I am reviewing in Griffith's E&M, and I find that potential is defined as zero at infinity (that bits fine). However, should not an object that distance from a charge be less than zero (negative) if it is closer than infinity? It seems it should as it has lost P.E. However, he doesn't seem to...

Hi everyone, I'm looking at MIT's opencourseware as a template. It seems the same textbook was used for Electromagnetism 1 and 2, even the same chapters, which seems really odd. For example, both EM 1 (in 2006) and EM 2 (current year 2014) studied Vector Analysis and Electrostatics from the...

Homework Statement The problem states, "Find the electric field a distance z above the center of a square loop (sides of length a) carrying a uniform line charge λ. " The hint says to use the result of example 2.1. Example 2.1 is a similar problem, but instead of a square loop you are asked...

I know there are a lot of similar questions here but just hear me out. I am going to start self-studying quantum mechanics in a few days. I think I am going to use the MIT quantum mechanics 1 lectures as a starting point. But books will be essential as I spend most of my time in school. I have...

Homework Statement Look at the attached file. 1) Why does Griffith simply say that the E-field of the amperian loop is parallel to the axis of the wire? 2) And how come ##\int \vec{E} \cdot d \vec{l} = -E(s) l ## ? Shouldn't it at least be ## E(s) 2l## ? Why the minus sign and ##l## instead...

I can tell this is simple, but I'm just not seeing it: (pages 146-147) Radial equation = d^{2}u/dp^{2} = [1 - p_{0}/p + l(l+1)/p^{2}]u Later... (having stripped off the asymptotic p^{l}e^{-p} parts) d^{2}u/dp^{2} = p^{l}e^{-p}{[-2l-2+p+l(l+1)/p]v + 2(l+1-p)dv/dp + p*d^{2}v/dp^{2}} And he...

Hi I am currently trying to learn quantum physics using David J. Griffiths textbook. However, in chapter 4 and 5 he lost me a little. I would prefer a textbooks that handholds me through solving the PDE's rather than just giving me the solutions. The topic of these chapters are: QM in three...

Homework Statement Consider the wave function $$\Psi(x,t)=Ae^{-\lambda|x|}e^{-i\omega t}$$ Where ##A##, ##\lambda##, and ##\omega## are positive real constants. (a)Normalize ##\Psi##. (b)Determine expectation values of ##x## and ##x^2##. Homework Equations...

In griffith's intro to electrodynamics (4rth edition), ch. 3, pg. 121. here is the second uniqueness thrm for the solutions to laplace's equation: the only part I'm confused about is, in the beginning where he says "in a volume V surrounded by conductors and containing a specified charge...

Please refer to the problem towards the end of page in the following link. It's related to discontinuity in normal derivative of magnetic vector potential across a current carrying surface. Prob 5.32 in Griffths. http://physicspages.com/2013/04/08/magnetostatic-boundary-conditions/ The...

I hope I am posting this question in the correct forum. I am in the second course in an upper level Electricity and Magnetism sequence (E&M II). We are using Griffith's Introduction to Electrodynamics as in the first course in the sequence. We covered chapters 1-3, 5, 7, and some of 8 in the...

Hi guys, I do not really understand the explanation bit where he describes the "term left out" of the integration. Why is there any term left out? I thought it's rather straight forward that E = E(inside) + E(outside)?

For example Griffiths' Electrodynamics, and Quantum Mechanics seems popular. and the prices are expensive. I'm curious about how much money the author make by selling these books.

In a normalization chapter there's an equation(1.21) which says: d/dt ∫|ψ(x,t)|^{2}dx=∫∂/∂t |ψ(x,t)|^{2}dx there was a description:(Note that integral is a function only of t,so I use a total derivative (d/dt) in the first expression,but the integrand is a function of x as well as t , so it's a...

Greetings, In Griffiths E&M, 3rd. Ed., on page 214, the following is part of the derivation of the continuity equation (the same derivation is shown on the Wikipedia article for the current density, under the continuity equation section: http://en.wikipedia.org/wiki/Current_density)...

According to Griffiths QM book, after he derived the stationary state solutions to the Schrodinger equation for a particle in an infinite potential well, which are just functions of sine, he claims that these stationary solutions are orthogonal and complete. I agree that they are orthogonal...

My question is in Griffiths Introduction to Electrodynamics 3rd edition p48. It said Two expressions involving delta function ( say ##D_1(x)\; and \;D_2(x)##) are considered equal if: \int_{-\infty}^{\infty}f(x)D_1(x)dx=\int_{-\infty}^{\infty}f(x)D_2(x)dx\;6 for all( ordinary) functions f(x)...

I am working through chapter 10 of Griffith’s electrodynamics (for fun and in my spare time). While I don’t have a formal bucket list, getting to an understanding of how Newton’s third law is not as straightforward for electrodynamics has been on my mental bucket list. I am an engineer not a...

As the title says, I've worked through all of Griffiths in my EM classes. It's a great book, but I plan to continue in the field of applied EM so I now need something more advanced. I'm more interested in the engineering/applied side of things, so I'm interested in stuff like materials...

I am pretty much satisfied with the example of a rotating shell example 5.11 pg 367 griffiths electrodynamics.on many ocassions he chooses cartesian coordinates before integration (see 5.10 too) , integrates and finds w×r along y direction .then he manipulates w×r, and writes it down in...

I do not understand the following from Griffiths’ Electrodynamics – page 424 Equation 10.21. \nabla p = \dot{p} \nabla {tr} = … I’m not sure how much of this applies (I think my question is on the math) but p is the charge distribution, tr is the retarded time. Is this an...

Author: Robert B. Griffiths Title: Consistent Quantum Theory Amazon Link: https://www.amazon.com/dp/0521539293/?tag=pfamazon01-20

Homework Statement This question is regarding clarifying some reading in Griffith’s Electrodynamics, page 224. “deriving the curl of B” In particular it’s less on electrodynamics and more on some vectors or vector calculus. The book states: we must check that the second term integrates to...

Homework Statement I am unsure as to a step in Griffiths's derivation of the quantum harmonic oscillator. In particular, I am wondering how he arrived at the equations at the top of the second attached photo, from the last equation (at the bottom) of the first photo (which is the recursion...

Don't care for Griffiths, and I think it would make a lousy reference given how many important theorems, results, etc. are hidden in the problems rather than included normally. I'd like a book that ideally has derivations of all the relevant formula and CONCEPTUAL descriptions of phenomena...

Homework Statement Greetings, In Griffiths, Introduction to Electrodynamics, example 5.5 (page 216), calculating the B field a distance “S” away from a current carrying wire. l' (dl’) is the horizontal current carry wire – will be segmented to dl’ tan(\theta) = \frac{l’}{s} In the next...

Homework Statement What is the probability that an electron in the ground state of hydrogen will be found inside the nucleus? a) First calculate the exact answer, assuming the wave function \psi(r,\theta,\phi) = \frac{1}{\sqrt{\pi a^3}} e^{-r/a} is correct all the way down to r=0. Let b be the...

Author: David Griffiths Title: Introduction to Electrodynamics Amazon Link: https://www.amazon.com/dp/0321856562/?tag=pfamazon01-20 Prerequisities: Calculus 1,2,3, Basic E&M Level: Upper-level undergrad Table of Contents 1. Vector Analysis 2. Electrostatics 3. Potentials 4...

Author: David J. Griffiths Title: Introduction to Quantum Mechanics Amazon Link: https://www.amazon.com/dp/0131118927/?tag=pfamazon01-20 Prerequisities: Contents: Contents PART I: Theory 1.The Wave Function 1.1 The Schrodinger Equation 1.2 The Statistical Interpretation...