Propagation Definition and 487 Threads

Homework Statement Consider the points (x, y) = (0,0) and (100,10). Calculate the unit vector u pointing from the first to second. If each coordinate has an uncertainty of +/-2, calculate the uncertainty in u using propagation of error, but making reasonable approximations based on the values...

I have a question about the propagation of light, I am not that technically versed in all the matters involved so it is a philosophical question. The principle of relativity, deducible from Newton's laws, has long been considered verified experimentally, most famously by Michelson-Morley's...

Homework Statement I have completed a lab that uses a Wheatstone bridge to find an unknown resistance utitlizing a resistance box and a slide wire. This will yield the unknown resistance from the following formula... Ru = unknown resistance Rs = known resistance from the resistance...

Hi. I'm not even sure if I'm posting this in the best forum! I'm having a lot of trouble grasping parts of this paper.. Eur Biophys J. 2009 Jun;38(5):637-47. Epub 2009 Mar 4. A nonlinear model of ionic wave propagation along microtubules. Specifically, they use a phase space plot that...

Homework Statement A planar waveguide is formed from a 10mircometer thick film of material of refractive index 1.46 sandwiched in material of refractive index 1.45. Calculate the number of modes of propagation that guide support at the wavelength 1.3mircometer, and estimate the propagation...

I need to know the propagation velocity of a transverse wave on a long thin bar or rod. In terms of material properties, such as E and density, and in terms of geometry such as I (2nd moment of area). I'm a physics grad, so reasonably versed in such things. But can neither find nor derive...

Hello, if we assume that the wave propagation-speed in a medium is v, does this imply that there is an "upper-bound" for the maximum frequency that a perturbation can produce? Or are these totally unrelated quantities? Thanks!

I'm trying to get an intuitive sense for errors and picked some random numbers: x = 2.5 +/- 0.01 find f(x) = x³ d f(x) / dx = 3x² d f(x) = 3x² dx = 3(2.5)² 0.01 = 0.1875 What I don't get is why f(x - Δx) ≠ f(x) - 0.1875 and why f(x + Δx) ≠ f(x) + 0.1875 Where did I go wrong in...

Hi i have to write the split beam propagation program in matlab. My medium is 5*5*5 (in mm each). I have to consider the propagation in z direction. I have divided my spatial coordinates(bot x,y) in 64 parts and represented them as a 1x64 matrix. So, I have defined the gaussian beam in the...

My doubt arises because I couldn't understand how a Poincaire Sphere gives us info about direction of propagation of wave. Now as we know Poincaire sphere is a neat way of showing the polarization state of an TEM wave. Now ,let me give an example to illustrate my doubt : - Let us take a...

Homework Statement Find the equivalent resistance viewed by A and B and its equivalent uncertainty: http://img707.imageshack.us/img707/5040/dadadadaz.png R1 = 10ohm, 5% tolerance. R2 = 2ohm, 1% tolerance. R3 = 5ohm, 5% tolerance. R4 = 15ohm, 1% tolerance. The Attempt at a Solution...

Hi I've looking into path loss for electromagnetic waves and it's quite straight forward to figure out how it works in free space by looking at the free space path loss formula (http://en.wikipedia.org/wiki/Free-space_path_loss). It has not been that easy figuring out how another medium...

Hi All Is the following statement true: Electromagnetic energy requires a wave medium to propagate. (The way free electrons in a copper conductor transfer energy in an AC circuit. Electrons can act as wave medium). If it is true, How does EM energy travel in space. Can gravity act as a...

Hello everyone. I have tried to do as much research as my layman mind will allow on how an electromagnetic wave propagates in relation to how a sound wave for example does. I understand that an acoustic wave is longitudinal and works on compression and that a light wave is a transverse wave...

We were taught in the vibrations and waves lecture course that the solution to the wave equation for traveling waves is of the form ψ(z,t) = Acos(wt-kz). In the Electromagnestism course we learned that EM waves are traveling waves and have the solution E = E0cos(kz-wt). I know that changing...

erm, ok let's say i have a value, with uncertainty, like y = 10 ± 3 so let's say i multiply y by 2, then it becomes 20 but does the uncertainty becomes 3 x 2 = 6? , hence y = 20±6 ? what about divide? does it becomes 1.5? i roughly understand fractional uncertainty and propagation...

when an electron neutrino is produced in the sun, it have the total energy of E. the total energy E have the relation with mass and momentum as E2=p2+m2. during the journey of its propagation from sun to earth, the electron neutrino change their flavor to muon neutrino which have mass m'...

Homework Statement You have a rubber cord of relaxed length x. It be- haves according to Hooke's law with a "spring con- stant" equal to k. You then stretch the cord so it has a new length equal to 2x. a) Show that a wave will propagate along the cord with speed...

I'm working on trying to understand wave propagation. In particular, I'm trying to understand directional wave propagation in elastic and inelastic materials. Is there an ideal theoretical medium in which it is possible to propagate waves in an entirely directional i.e. straight-line manner...

Homework Statement What are the uncertainty propagation formulas for: Area of a rectangle Density of a sphere Height of an opposite side wall calculated by tan(θ)=o/a ResistanceHomework Equations Area of rectangle= side A *side B Density of a sphere= mass/(4/3piR^3) tan(θ)=opp/adj Resistance=...

Homework Statement Consider y_1=Asin(5x)exp(-2t) y_2=Aexp(4ix)exp(-2it) y_3=Asin(2x-5t)exp(-2t) (i)which one represents a wave that propagates at constant speed with no change in its profile (ii)Confirm it satifies the wave equation and obtain the wave velocity (iii)Comment...

Recently I came across an example for working out error propagation, and I'm having trouble following the steps: A = 100 \pm 1% B = 10 \pm 1% AB = (100 \pm 1%).(10 \pm 1%) = \left\{1000 \pm \left[\left(100.1\%\right) \pm \left(10.1\%\right)\right]\right\} // get confused here, how does...

From reviewing previous posts on the subject, I understand that the E field and B field propagate in-phase through space. From this information, does it mean that at a specific space and time the E and B fields will be zero? If we had an instrument to determine the E and B field at specific...

We have consistently been told that light propagates through a vaccuum. My question is twofold: What is this vacuum vacant of? (Unless we could reach temperatures below -273C, I cannot imagine that there is somewhere that electromagnetic waves are NOT present) Where and when was this bold...

In the electromagnetism theory, the phase factor or constant (usually BETA) in wave propagation for lossy medium has the unit rad/m. I understood that it must be interpreted as the amount of phase shift that occurs as the wave travels one meter. However, differently of the attenuation...

light doesn't cotain any charge then how it fluctulate the electric and magnetic field in vacumn or medium.

Suppose you know the phase of a wave is given by \phi_1 = \vec k \cdot \vec r - \omega t. How can you determine in which direction this wave is propagating? I guess, more specifically, how does a wave described by this phase differ from a wave described by the phase \phi_2 = \vec...

well I'm so confused with this, the maximum speed of magnetic and electric fields is c ... however when one tries to reduce an electic current generating a magnetic field into one charge Q moving with speed v from one point to another in a distance x, then the magnetic field intensity will...

the equation for wave of speed(v) relating tension(F) of string is v= sqrt(F/μ) says that as mass density μ increases, velocity of propagation decreases. but why does sound wave's propagation speed increases in a denser medium like water compared to air?

I'm doing a lab write-up and I've run into a snag. I'm trying to do propagation of error in a product, but one of my quantities that I'm multiplying is 0. The propagation of error formula for z = xy is \left ( \frac{\Delta z}{z} \right )^2 = \left( \frac{\Delta x}{x} \right )^2 + \left...

Hi all: In magnetic resonance imaging such as human brain head image, I select several regions of interest (ROI) with the size of 8 pixel. Thus the average value and standard deviation are computed for each ROI. Now I want to evaluate the average value over different ROIs. For example...

I am working on some interesting topics which relate to the speed at which gravity propagates. My question is this: within the frameworks of special and general relativity (or any other widely accepted theory, for that matter), is it necessary for gravitons/gravity waves to propagate at...

Homework Statement For my lab work, I have created a theoretical model that goes something like: T = \sqrt{\frac{ks^2}{x \sin \theta \cos^2\theta}} where k is a constant, and the variables to be differentiated are x, theta and s. How do I find the error of T? I can find the errors of x and...

The idea of a wave packet is confusing a bit. First let me tell you what I have understood about it. A wave packet is obtained by the superposition of harmonic waves of nearby frequencies which represents a matter wave. It is well known fact that the width of a moving Gaussian wave packet in...

If you connected a DC or AC source to the end of an single, infinitely long, straight wire suspended in free space (separated from anything), would propagation occur along the line?

Hi all.. I am just stuck upon something very trivial.. We know that E and H fields in an EM wave are perpendicular to each other.. I was also told that they are respectively perpendicular to direction of propagation.. Is it correct? are there any conditions for this to hold..??

Homework Statement A wave is sent down a cable. When it hits the end of the cable a reflected wave is sent back. You are given the: - time between the initial and reflected pulse - the amplitude of the initial and reflected pulse. You also know the length of the cable (you may not need...

I am generally an "artsy" person, though I am interested in science, too. I am curious about EM waves, particularly how they get started and what determines their amplitude and direction. I've read that an oscillating charge can generate a magnetic field, though I'm a bit confused about what...

I was watching this E & M lecture -http://www.youtube.com/watch?v=XtHsVSW2W3E&feature=SeriesPlayList&p=C2CEECFD938FD494&index=28 There is a demo at ~45:00 into the lecture, where a structure with metal bars is introduced between 2 waveguides. I am trying to figure out what exactly happens...

all i have under my belt is a high school physics class, so please bear with me. i have a pretty good understanding of light and waves, but this question still gets me. and nowhere can i find a decent answer, or rather, and answer i can comprehend. if EM waves don't require a medium, then what...

I am doing a calculation involving taking three or more temperature measurements and then plotting them against another quantity (dependent). I get a relationship that is pretty linear, so I take the line of best fit to obtain an equation with a slope and an intercept. Now, my question is...

I know my impedance minima and their associated frequencies for a particular coaxial cable. How would I go about deriving an equation that will let me calculate the speed of propagation and the dielectric constant? My only hint is to consider the case for which Z = 0 but I don't know where to...

I am trying to do a simple calculation on radiation propagation using Cs-137 as an example. Cs-137 has the following properties: Activity = 3.400e+15 Bq/kg Decay energy = 188.096e-12 J (1.174 MeV) This results in 639.526e+03 J/s of radiation, which is then inversly proportional to...

Excuse me if this question is obvious. Do mechanical waves propagate through loudspeaker diaphragms (whether they be elastic or rigid) in the same way that acoustic waves propagate through waveguides albeit a different medium? As far as I understand, reflections occur at the boundaries of the...

i have a doubt in wave propagation in solids wave propagation i have studied in school is in continuous medium but real mediums are discreate how will we understnd wave propagation in them -for wave to transfer from one particle to next takes infinitesimial time but since in continuous medium...

Hi, I am trying to represent my data in log2 form rather than "fold change" and I am embarrassed to say I can't remember how convert the error. For example, I have x=3.96 (mean), deltax=0.28 (standard dev). Thus, log2(x)=0.598. But how do I convert the error?? I know how to do it for...

Homework Statement I have conducted an experiment which attempts to calculate the range of the visible light spectrum. Basically white light was shined through a diffraction grating (300 lines/mm) and diffraction theory is applied to calculate the wavelength. So, here are the variables...

Homework Statement The area of a flat, rectangular parcel of land is computed from the measurement of the length of two adjacent sides, X and Y. Measurements are made using a scaled chain accurate to within 0.5% over its indicated length. The two sides are measured several times with the...

Hi, Can somebody point me in the correct direction of learning about Schrodinger Equations in relation to Wave propagation. I came across Schrodinger Equations in some texts but couldn't quite understand some background. Most of the time the author used it from nowhere. Really appreciate if...

This is probably a silly question -- but I have been thinking about it, and I can't convince myself. So, I'd be greatly happy if you could solve my apparent "dilemma". In electromagnetics, for sinusoidal voltages, we use the phasor notation and express a positive traveling wave ( +Z...