Propagation Definition and 457 Threads

How does the Cut-Back method work experimentally? The Cut-Back Method is a method to determine the propagation losses of fibers or waveguides. I have found tons of articles stating they used this method in comparison but no detailed information on how one can execute it successfully...

for a wave of this type, for example: f = cos(x+2y -vt) What is then the definition of the direction of progation in the x-y plane? Because either way you go in the x-y plane the wave changes.

Homework Statement I conducted an experiment which involves measuring two distances (Y and L) and have used tan to determine the angle, then finally calculated the sine of the angles for use in my analysis. I have uncertainties in both length measurements and am unsure how to propagate the...

I would like to ask some questions to confirm if what I have acquired so far are correct, please point out my faults if any. If all the below statements are too bulky to read, my question is actually as short as: \psi (x) = A{e^{-j(kx - \omega t)}} What is the propagation direction of this...

please help by telling me whether my approach to solve the problems are right or wrong. please refer to the ATTACHMENT for the questions and my approaches... your help is highly appreciated!

I have problem regarding the propagation of error since the equations involving mixtures of multiplication, division, addition, subtraction, and powers. Please help me to clarify whether my attempts are right or wrong.

Dear all, Let me introduce the topic first, so this thread can be put in the most appropriate subforum. Belief propagation, also called message passing, is a method that communicates messages between nodes on graphical model (for example a Markov random field) and where the messages...

How can the mass of a hole is larger than an electron?I want to know what a hole signifies and the mass energy required for it to propagate in the semiconductors for constituting current.

You measure the mass of the cylinder to be m = 584.9 +- 0.5 grams, and you measure the length of the cylinder to be L = 18.195 +- 0.003 cm. Just like in the lab you performed, you now measure the diameter in eight different places and obtain the following results. Diameter (cm) 2.125 2.090...

Can anyone tell me how light waves propogate. Will a photon have a trailing cone?

Why sound waves propagate through liquids as longitudinal waves, and it is propagate on the surface of the liquid as transverse waves?

If I have two independent variables x,y, and two measurements, m1, m2 with errors. And the dependence is thus: m_1 \pm \delta m_1 = f[x,y] m_2 \pm \delta m_2 = g[x,y] Now in my case, f and g are complicated expressions of x and y with no simple solution. (Actually I think i can...

I'm reading my course book on ELectromagnetism and it is talking about a wave moving in the y-z plane but with polarisation in the x-direction, and it says that the equation $$\mathbf{E}=E_0 2i sin(k_0 z\ cos \theta) exp[i(k_0 y\ sin \theta - \omega t)]\mathbf{e}_x$$ Shows that there is no...

Hi, When using data in calculations, errors can be introduced by the calculations themselves; A common example of this kind of data is the atomic mass of some element; The data might be reported by NIST as: 190.233(20), which indicates that the mean is 190.233, and the maximum likelihood...

Homework Statement This should be very simple: Given the following (boundary frequency for photoelectric effect): \nu = \frac{\phi}{h} what would be the error on \nu? Homework Equations The Attempt at a Solution \varphi and h are both determined through linear regression (y = mx + c). Where...

I am studying the vibrations in a coil spring, and want to confirm with others that my derivation is correct. I found that for small oscillations the spring is described by the 1-D wave equation, with wave speed k*l^2/m. where k is the spring constant, l is the spring length, and m is the...

In my book on waves, it is said that, given a flexible string under tension, a derivation of the transverse velocity v can be given by viewing the string in a frame moving uniformly with a velocity equal to that of the wave itself. The velocity can be found by requiring the uniform tension of...

I was wondering if someone could please help me understand a simple problem of error propagation going from multiple measurements with errors to an average incorporating these errors. I have looked on several error propagation webpages (e.g. UC physics or UMaryland physics) but have yet to find...

This is my first post and I'll admit I probably don't even know enough to be dangerous. Any how what I have is a a 3' long 6" dia tube that is functioning as a muffler for a boat. It has two 4" dia inlets mounted perpandicular to the length of the tube at 28" on center and two 4" oulets mounted...

Hello all, I have been trying to figure out a clear rule for parallel propagating vectors on spheres, such as in the wiki http://en.wikipedia.org/wiki/File:Parallel_transport.png. There seem to be lots of rules that are proposed in this forum and online, but they often don't work well to...

hi i have some measured values that refer to a simple experiment where a stone was thrown along a fixed length and now i have these values for the time the stone needed time 13.8 13.7 13.9 13.5 14.4 14.6 14.1 14.3 13.9 14.7 i was asked to explain how many decimal places one would write...

Hi guys, So I'm writing up a physics lab and I have a bunch of data points. All of these data points have both x and y error bars. The relationship between x and y is linear and so I've made a line of best fit using Python passing through the data. Now the slope of that line of best fit...

Suppose F = x/y dF= \frac{\partialF}{\partialx}\deltax+\frac{\partialF}{\partialy}\deltay This gives dF=\frac{\deltax}{Y}-\frac{x}{y^2}\deltay That is, the partial derivative of y comes out negative. Should i leave it as a negative? I see no reason to take the absolute value of...

I have couple questions about this and I was hoping someone with some stats knowledge could clarify. First, when people report numbers such as 10 plus or minus 5, what does the 5 mean? Is it the standard deviation or the confidence interval or the variance? What is the relationship between...

I have a system of coupled ODEs which tells the propagation of power Pi in an optic fiber. \frac{\partial P_i }{\partial z} = \left (N\sigma - 1 \right ) P_i where N = \frac{\sum_i \alpha_i P_i}{\sum_i \beta_i P_i + 1} If the signals are copropagating, there is no problem since...

1. Why do waves propagates on a string? I mean, when we create a disturbance on one end, it affects all the string. How can it be? 2. How can there be a continuous flow of energy along a medium when the particles of the medium simply oscillate about their equilibrium positions? 3 Intuitively...

I'm figuring this belongs in quantum - sounds like a quantum effect. http://www.opticsinfobase.org/abstract.cfm?id=63756 (my emph) There's lots of papers like this ... also been in the blogosphere: Sounds like some people are claiming to have done it for real...

I'm slightly confused about the speed at which "electricity" flows through neurite (i.e. dendrite etc) as per cable theory (http://en.wikipedia.org/wiki/Cable_theory). In standard electrical circuits, we have two velocities - the drift velocity of the electric charge and the velocity of the...

Homework Statement A wave is driven at z=0 with constant real frequency ωr propagates in the z direction, for z>0 the amplitude varies as: A = A_0 e^{i\omega_r - ikz} where k is complex k=k_r - i k_i if a wave with spatially constant amplitude and purely real wavenumber kr were...

Homework Statement I would like to know the speed of the propagation of nerve impulses in A B C D fibers Homework Equations The Attempt at a Solution

What is the difference between normal modes and propagation modes? I am confused. I know that normal modes are natural modes of vibration of a system. And, propagating modes are ... ? Thanks.

I've read that ionosphere mirrors the short radio waves (25-30 MHz). So 2 questions: Why this happens? There is material on the internet, but it's rather complicated for me so far, I've just started to study physics. So I'd appreciate if someone explains this in more or less simple way. Why...

Hi I can't proceed imagining the matter after this point... For a propagating wave: The medium particle gains energy to move.. Question 1: what makes the particle to move up or down, what is the force acting upon it. The wave sinusoidal pattern shape that travels across the medium...

how to prove that a wave given as A.exp[i (wt - kx) ] is moving in positive x direction ? similarly, how to prove that a wave given as A.exp[i (wt + kx) ] is moving in negative x direction ? Thanks a lot

My first posting after joining today so starting off "light" - I know a terrible pun but please be kind as I will ask a lot of basic and seemingly dumb questions from my simple mind in my quest to learn a lot as quickly as I can! I will try to word this as best I can but, how exactly do EM...

I was just reading about EM wave propagation and had two questions I would appreciate an answer to. 1-I read how the electric and magnetic fields of an EM wave oscillate sinusoidally and perpendicular to each other and the direction the wave is traveling. Is there any significance or special...

Not sure if this is the right section to post this.. I have 3 measurements and was trying to take the average of the measurements and calculate the error of the average: replicate 1 = 8.9 (+/-) 0.71mg replicate 2 = 9.3 (+/-) 0.69mg replicate 3 = 8.8 (+/-) 0.70mg I get an average of 8.9333...

Not sure if this is the right section to post this.. I have 3 measurements and was trying to take the average of the measurements and calculate the error of the average: replicate 1 = 8.9 (+/-) 0.71mg replicate 2 = 9.3 (+/-) 0.69mg replicate 3 = 8.8 (+/-) 0.70mg I get an average of 8.9333...

Homework Statement I am having trouble calculating uncertainty when a number is added to a value with uncertainty. M = 350g a = 0.624 \pm 0.001 µk = 0.07 g = 9.80 m/s2 Homework Equations T = M*a + µk*M*g The Attempt at a Solution T = (350g)*(0.624 m/s2) +...

Homework Statement Given the following EM wave propagating in vacuum, find the direction along which the electric field oscillates and the direction of propagation of the wave: \vec{E} = (-3\hat{i} + 3\sqrt{3}\hat{j}) 10^4 e^{i[\frac{\pi}{3} (\sqrt{5}x + \sqrt{5/3} y10^7 - 8.1246 *10^{15} t]}...

Completely new to the concept of errors and don't know how to approach this... Calculate value and error in Z Z= 2AB^2/C Where A= 100 Error in A= +/- 0.1 B= 0.1 Error in B= +/- 0.005 C= 50 Error in C= +/- 2 Plugging in the numbers Z= 0.04 How do you carry the errors...

1-In a bottle of water,transverse waves propagte on the surface of water,while lognitudinal waves propagate in depth..what explains this? What makes different kinds of waves propagate through water not the same kind? You may tell me that is not true because surface waves propagates on the...

Hello, why an electromagnetic signal propagate as wave? Wouldn't be more normal that electron travel in a beeline? Thank you.

Homework Statement I want to measure the size of my back yard. I estimate that I can measure the length and width of the yard using a tape measure to an accuracy of 0.05m. I find that the length of the yard is 8.6 m and the width is 7 m. Calculate the perimeter of the yard and its...

A while back, one of my undergraduate physics professors gave an argument for why the uncertainty in a function or quantity F is given by \Delta F = \sqrt{^{N}_{i-1}\sum(\frac{\partial F}{\partial x_{i}})^{2}(\Delta x_{i})^{2}} He argued to think of a right triangle and think of...

Why do transverse waves propagate through solids , while logitudinal waves can only propagate through fluids?? I'm still confused about this

Hello, Given a 3D gaussian beam incident on a lens at an angle relative to the optic axis, with phase and amplitude on the incident surface known, what is the simplest way to find the phase and the amplitude after propagation through the lens? Sasha

Would gravitational waves propagating through space-time at the speed of light be affected by the curvature? Or are they independent? Why does the spinning of a binary pulsar cause a gravitational wave when there is no change in mass other than the loss of photon energy? Doesn't this object...

A steel wire of radius 0.65 mm is subject to a tension of 11.29 N. Steel has a volume mass density of 7800 kg/m3. Find the velocity of propagation of transverse waves on this wire, in m/s. I found the cross sectional area of the wire but I am not sure where to go from there. I know I need...

This is an issue I am running into at the beginning of my physics course. Homework Statement Given distance and time in minutes, calculate the time in hours (part of a larger average velocity question) and graph over 170minutes. Include error bars in the graph Homework Equations...