Explanation Definition and 982 Threads

Hello, I am wondering what is qualitatively speaking the effect that causes a material to be paraelectric? I do know that it strengthens an applied external electric field with alignment of electric dipoles. What is the mechanism that causes this alignment of dipoles? In a traditional...

I have a question about Taylor expanding functions. For both cases I can't get my head around why things are the way they are. I just don't see how one would perform Taylor expansions like that. The first: The starting point of a symmetry operations is the following expansion: f(r+a) = f(r)...

Hello , I have tried to solve a system of differentiel equations with mathematica that is presented as follow X[t_] = {x1[t], x2[t], x3[t], x4[t], x5[t], x6[t] , x7[t], x8[t], x9[t], x10[t], x11[t], x12[t]}; system = MapThread[#1 == #2 &, {X'[t], A.X[t]}]; where the matrix A is...

Hi, :) I have some basic knowledge of matrices and vectors. mI understand some of their practical applications in real life. This idea of vector is entirely new to me. What is a vector in simpl terms, or to begin with? Please try to explain with some simple practical explanation. I would...

I recently learned that Kramers-Kronig relations can be applied to physical response functions, but I find it strange that for eg. the refractive index and absorption of a material cannot be independently defined, what is the explanation behind this from the point of view of the physics...

A single particle can behave like its interfering with itself by means of the following explanation (is it true or can you refute it?): Ballentine wrote in his 1970 paper "Statistical Interpretations of Quantum Mechanics": "As in any scattering experiment, quantum theory predicts the...

Hi, I've looked everywhere for an explanation of this, including this forum, and none of them seem to satisfy the level of detail I am looking for. More specifically, I am interested in how processing units used a fixed setup of logic gates and transistors to perform universal computation...

Is this explanation of uncertainty principle from wikipedia correct? Is this "compressing" the Fourier series/integral? Because the function is not periodic, and with infinite frequencies some of then would put make the speed greater than c "According to the de Broglie hypothesis, every...

http://imageshack.us/photo/my-images/685/variablegaincontrol.png/"can someone please explain me the circuit schematic that i have attached because i can't understand it. Thank youhttp://imageshack.us/photo/my-images/685/variablegaincontrol.png/

Hey, I'll state first that I've obviously just been introduced to vectors and I have looked through the given material in class let alone watched "Khan Academy" and "Patrick JMT" video on Vectors but i can not really grasp the concepts. Question: In parallelogram PQRS let q = PQ and...

Quantum objects are particles, not waves. Particles are bundles of energy propagating on a field. It is the properties of the field that seem to give particles wave-like qualities. Thus in the Young's double slit experiment, a given particle goes through one and only one of the slits; it does...

I went through several threads about the integral of e^x^2 but I could not find anything about the proof why e^x^2 cannot be integrated as an elementry function. Could you explain why?

I'm doing LaPlace transforms for a circuits class, and I realized that I don't REALLY know what the S domain is. When you do Fourier transforms, obviously you're in the frequency domain and that's pretty easy to understand. The other domain you work in a lot is time. But up until now, I've just...

Hey all, Currently trying to revise products of disjoint cycles. I am struggling to get my head around the idea however. Its strange, i can generate disjoint cycles easily however i can't quite see the product of cycles. Mabye I've missed something. eg of what i don't quite get. What is...

For a college project, I'm researching quantum defect theory. In my study, I'm using emission spectra to determine the quantum defect, treated as the correction term in the denominator of the Rydberg equation. What I understand In general, the Rydberg equation is effective for Hydrogen...

I'm trying to read this: https://www.amazon.com/dp/1584883936/?tag=pfamazon01-20 On the pages 12-13 it says: The bold part is where lose the track. Why are quantities, which are invariant under permutations of roots, expressible in some certain way?

Force F= (2.0N)i - (3.0N) k acts on a pebble with position vector r= (0.50m)j - (2.0m)k relative to the origin. In unit vector notation, what is the resulting torque about a) the origin and b) the point (2.0m, 0, -3.0m)? Okay, I got the answers and their right. For both (-1.5)i - (4.0)j...

One common explanation of the concept of D.F. is this: Suppose you have n numbers (a, b, c,...) that make up a sample of a population. You want to estimate the variance of the population with the sample variance. But the sample mean m is being calculated from these numbers, so when...

According to my biology textbook, calico cats get their fur color mosiac from the random deactivation of one of their X chromosomes, by condensing them into barr bodies and displaying either the maternal or paternal X chromosome fur color only. IE each cell randomly deactivates either X and...

Homework Statement http://img23.imageshack.us/img23/949/unledto.png Go to problem b) [PLAIN][PLAIN]http://img850.imageshack.us/img850/5388/unledzb.png The Attempt at a Solution Now my question is why L + 2x? L is the height and x is the width, why are they adding them? I know...

Goal: to very concisely explain how & why certain people are paid a particular dollar amount (in the USA). I'll go first: In the US, compensation is generally based on the availability of labor, and the value added (expected revenue gain) by your work. Thus, skills which are very common but...

Why does light refract between the two mediums when transferring from one to another? And why is the refractive index different for different wavelenths/frequencies? Thanks in advance, fawk3s

Hi, I'm an undergraduate physics student trying to comprehend why the twin paradox is not a paradox. The standard reply usually amounts to this: the dude in the spaceship has to turn around at some point to come back to Earth. So he accelerated during his journey (by changing his direction...

I am not a scientist, however I am very interested in quantum mechanics and string theory at a basic level. One thing when learning about string theory that struck me as being particularly interesting is the branes described by the "M" theory. Let me start my query with three assumptions...

Hi, I've got a few questions about that common base colpitts oscillator. I am trying to simulate it but, I am not sure if the circuit is complete or is it missing anything? I have some formulas but not sure how to use them.I have some assumptions, are they right? 1. Capacitors R3 R4 nad R5...

I've just started thinking about this and haven't read much about the "simulation argument" yet, but is there anything unreasonable about using computational/information theoretic/Occam's razor arguments to argue that the simplest explanation for the universe is that everything is being...

Can somone explain to me about Magmas which have different chemical compositions have different temperatures i.e basaltic magmas erupt at about 1200 °C whereas rhyolitic magmas erupt at about 700 °C. what is the difference in chemical composition between these two? also why can the composition...

This question appeared in my exam . Q. A bullet of mass 41g travels at 960m/s. what wavelength can we associate with it? why does the wave nature of the bullet not reveal itself though diffraction effects? Ans.. i find de broglie wave length by formula lamda = h/mc but didnt...

Homework Statement I am reading an explanation on a trig identity but I am not fully understanding it... Angle MOP = Theta Angle POP' = Right angle Angle AOP' = (Theta + Right angle) Take OP' = OP ( WHY must it be equal?) Angle MOP + P'OM' = 90 ( I understand this) Angle MOP = Angle...

Could someone help me clear my understanding of spillage? I need to plot spillage vs. Mach number at for different fuel flow rates. It's defined in this problem that full mass capture is when Mach=0.8, fuel flow rate=.2506 kg/s. The other Mach number's are based on the other fuel flow rates of...

I thought others might be interested in this: http://arxiv.org/abs/1011.6142 As a nuclear physicist, I don't find it surprising to hear that neutron stars are superfluid. Nuclei are superfluid. I'm not clear on the relationship between superfluidity and cooling. Can anyone explain this using...

I have the following DE: y'=y*(1-y^2) And understand that y=0, and y=+/-1 are critical points I am confused as to which are stable/unstable and why. TIA

This APS page http://focus.aps.org/story/v22/st19 describes the classic experiment by Wu et al. in the 50's that demonstrated parity violation. It contains the following explanation: "[1] The magnetism of the nuclei can be thought of as resulting from their spin. With the nuclei aligned with...

This relates to a long standing confusion I have had about the Coriolis explanation for cyclones and anticyclones... The usual 'turntable' demonstration of the Coriolis 'force' is very intuitive. The demonstration relies on the ball/pen/pendulum not having any friction with the turntable and...

new explanation for AdS/CFT?? Here is a possible new interpretation of AdS/CFT. (Just humor me for a moment.) First, take a look at the pattens as photographed in Discover magizine: "Waves on a sphere follow the unpredictable Rules of Quantum Mechanics". (p. 53 of March 2011 Discover...

I'm in the middle of a Complex Analysis course, working on the proof for a theorem to calculate radii of convergence for power series; a formula that utilises lim sup. Unfortunately, either I've forgotten lim superior/inferior from 1st year Analysis or I was never taught it in the first place. I...

Homework Statement If my original echelon form is: 1 1 -2 1 | 2 0 3 3 3 | -3 0 0 0 1 | -4 and according to my notes that my teacher provided, the reduced form is: 1 0 -3 0 | 3 0 1 1 0 | 3 0 0 0 1 | -4 he noted that in the reduced form, the 1's in columns 1, 2, and 4 are...

I was reading through my mechanics of materials book (Mechanics of Materials 8th ed. R.C. Hibbler) learning about stress and came across example 1.6 pg. 28. while most of the example makes sense the last bit of part b) confused me. I am unsure as to why for Pcd he only showed the 22 kN force...

Hello According to general theory is there any explanation of tidal wave in sea due to gravitation of moon. How moon warp space time in such a way so that tidal waves are generated in sea?

Hi there. I'm a second-year physics student. I'm from Mexico (so please, forgive my english), and I'm on winter holidays. I've been studying Mechanics with the first volume of the "Course of Theoretical Physics", by Landau and Lifgarbagez, that awesome though hard book series. My study plan...

Credits to Matt Might, whomever he is: http://matt.might.net/articles/phd-school-in-pictures/

Homework Statement (Draw a diagram illustrating the direction of the electric current induced in a conductor as it passes through a magnetic field) Write a short paragraph in which you explain your reasoning for the direction of the current in your diagram refer specifically to the motor...

Homework Statement I have attached a link to the solution set of some questions from sakurai. But I don't understand clearly the solution of question number 5.29. link: http://www.people.virginia.edu/~7Erdb2k/homework/phys752/quantum.pdf" Homework Equations how did they found the 4x4 matrix...

Homework Statement A tennis ball is thrown from ground level with velocity vo directed sin 30 above the horizontal. If it takes the ball 1.0s to reach the top of its trajectory, what is the magnitude of the initial velocity? Homework Equations The initial vertical component of...

Can someone explain to me how to show (x\y) union (y\x) = (x union y) \ (y union x) using only the main set theory laws for union, intersections and difference.

I've done plenty of problems over the course of my degree that involve waves passing through slits of widths comparable to their wavelengths, and spreading out. As far as I'm aware though, I haven't been told what is actually going on there, just that it does happen. I know that we can...

I need explanations of some observations - 1) How do they remove the anti-theft tags from clothes (mechanism behind it)? 2) How do trolleys no matter how heavy stick to a cartveyor? 3) Why do we need to apply more force to close the door (not throughout - just before complete closing) of a...

Pls give me defination and Explanation of Farday's Ist Law and 2nd(Electro Magnetic Inducation) in easy word of English,,,thanks

I wonder whether Dirac explanation of paradox of negative energy solutions of his equation is viable. Of course this paradox is absent in QFT but if we treat Dirac equation as an equation for wave function of electron the negative energy solution are a puzzle. Acording to Dirac we don't...

Hi I am new on here and also new to science. I am in College getting my Biology 12 and Chemistry 11. I am having a really hard time understanding the difference between the ionic and the covalent bond. I am having trouble understanding: a) the net charge that creates an ion b)the ionic...