Propagation Definition and 487 Threads

Hello. I have measured the period of the pendulum T=2.18 +/- 0.02 which is consistent with the true period 2.19865... so I expect myself to find a consistent value of g if I apply the formula propagating the error in the right way. I get g=9.96 +/- 0.2Why?

Hello everybody. I have a free scalar in two dimensions. I know that its propagator will diverge for lightlike separations, that is t= ±x. I have to find the prefactor for this delta function, and I don't know how to do this. How do I see from, for example, \int \frac{dk}{\sqrt{k^2+m^2}} e^{i k...

Stumbled upon this problem lately. Maybe someone could help me clarify some subtleties I do not see? 1. Consider the propagation speed ##c## of periodic surface of gravity waves with wavelength ##\lambda## and amplitude ##a## in water of depth ##H##. Let ##\rho_{a}## and ##\rho_{w}## be the...

Hello, I'm having trouble with a lab report. The experiment conducted was we used an angled air-track and a timer to determine the speed at which an object slid down the track and its acceleration. The final average acceleration we calculated was (61.034 +- 2.227)(cm/s2) We're then given a...

Hi there, can anyone please advise how the size of an obstructing object affects the propagation of an RF transmission? Eg, for instance does refraction only occur in objects that are larger than the wavelength or does it occur in objects smaller than the wavelength? I can find heaps of info...

On a small island there are 25 inhabitants. One of these inhabitants, named Jack, starts a rumor which spreads around the isle. Any person who hears the rumor continues spreading it until he or she meets someone who has heard the story before. At that point, the person stops spreading it, since...

Hi I wonder if anyone could advise how a radio wave would propagate around a metal object? Basically, I have a GPS antenna and due to mechanical issues the antenna is obscured by a mounting screw that sits in front of the antenna by about 2~3cm. I understand that the radio wave would become...

Is the propagation of a wave simple harmonic motion? Simple harmonic motion is defined when the restoring force is proportional to the displacement. Hooke's Law F = -kx is an example. However at my level of understanding I have not yet read about the relationship between forces and waves and...

Hello, We read very often that wave propagation électro-magnetism is the result of an interaction between electric field and magnetic field. However, Maxwell's equations are not causal. These equations have no delay between electric field and magnetic field, they simply pose relations...

Not sure if I'm putting this in the right place, but here's my issue: I'm putting a ultrasonic transducer against glass to try to vibrate/move water on the other side of the glass. I can get enough power through the transducer to physically move the glass, yet I still can't get water to move...

Homework Statement So I am calculating the error for something and I am getting really weird values. So I know that the value for the Inductor is 24.97 +- 0.005 mH and that for the capacitor is 105.7+-0.0005 nf. So I am finding the value for the resonant frequency Homework Equations...

Homework Statement The density of a cylinder is calculated from the following data: ##m= (2.8±0.8)g## ##d = (2.2±0.1)cm## ##h = (4.0±1.0) cm## What is the error on the density, before rounding, in ##\frac{g}{cm^3}##? Homework Equations ##V = \pi r^2 h = \frac{1}{4} \pi d^2...

Hi I am trying to find the equations of a charged particle inside a dipole & quadripole. Practically, I need to write a simulation program for it which assumes a beam passing through a dipole-quadripole-dipole which are setting around an arc. Is there some recommended literature ? Of course...

Homework Statement I am taking a dataset of intensity vs. frequency (which I'll call dataset I_1), and fitting it with a linear model (I_mod). I want to divide another intensity vs. wavelength data (I_2) by this fitted model to get fractional changes in the second data set compared to the...

My goal is to find the uncertainty δd in the following equation. d=C_1 \frac{1}{\sqrt{V}} \frac{1}{D} C_1 is the collection of constants \frac{2Lhc}{\sqrt{2m_e c^2 }} D is a value measured in meters with an uncertainty δD = 0.001 m and V is a value measured in volts with an uncertainty δV =...

I am trying to determine whether a burn would propagate faster through hydrogen or helium. My initial guess is helium due to the higher mass. I also think this is true in stars. Anyone have an idea on burn propagation and how different masses of material would affect it? Is my first...

Consider a pole of 1 light second long in the ##y## direction (the vertical line(s) in the enclosed figure). It is moving in the ##-x## direction. According SR, the pole's length is not contracted because its length is not parallel to the propagation direction. However, given the time of flight...

Photons propagate in a certain direction. When it encounters an atom on its way, and an energy of photon is equal to the energy difference between some levels in the atom photon can be absorbed. But, what happens if an energy of the photon does not match energy difference between levels in...

Hi, This is just a quick question. If wavenumber is a variable with some standard deviation Δk, how do I propagate this spread when converting from wavenumber to wavelength? Is it just 2π/Δk or is it more complex than that? Thanks

Hi everyone, I have been studying transmission lines and it got me thinking. If we have a series circuit which has two equal length transmission lines with the same Zo but with different velocity factors how does this effect the wave velocity through the circuit? Do the waves travel...

Hello everyone, I am going to do a paper that has something to do with wave propagation in a medium, but I am new in this area, so can you guy suggest any book or paper on introduction to the propagation of wave in fluid, my have a solid background in mathematics and mechanics , thank you very much

I want to understand what exactly is Maxwell's theory of wave propagation and what is its physical intepretation?

Hi~ Actually I am fine with calculating the delay but I haven't got the concept clearly enough. Both nmos and pmos have their equivalent RC models. I understand how the RC model of nmos works when its on or off but I don't get how the pmos turns out this way. When its off, the upper part...

Homework Statement E(x,y,t)=(2i/sqrt(5)) + (j/sqrt(5)) Eo cos( 2pi(1/lamda)[2x/sqrt(5) - y/sqrt(5)]-[ft] ) Homework Equations I Know k =2pi/lamda for 1D wave I know K vetor=k dot r I know K vector shows the direction of propogation, and must be perpendicular to E and B. The Attempt at a...

Hey all, I'm working on a project now where I am using a solenoid driven at a 10Hz AC current to create a magnetic field on a solid piece of low carbon iron, and then using a smaller solenoid to capture the magnetic flux coming from the iron. By measuring the phase of the resulting waves...

Homework Statement Suppose we measure N pairs of values (xi, yi) of two variables x and y that are supposed to statisfy a linear relation y = A + Bx suppose the xi have negligible uncertainty and the yi have different uncertainties \sigma_{i}. We can define the weight of the ith measurement as...

Homework Statement Not exactly a homework question, but rather a section in Statistical Data Analysis: Suppose there is a pdf y(x)[/SUB] that is not completely known, but μi and Vij are known: Homework Equations The Attempt at a Solution I understand how <y(x)> ≈ y(μ), My confusion: Why...

Hi I am very confused at determining the type of elastic wave in a vibrating body. For example, an elastic solid is flexuraly vibrating in one of its resonant mode. There should be elastic wave excited from this vibration. But, my question is which wave will be excited through it...

Just a quick question, would propagation of uncertainties with the partial derivatives still give the right answer when you only have one variable?

Hello, I am having quite a bit of trouble really grasping Brillouin Zones and their relation to phonons, energy propagation, etc. I've got a few questions, and there will probably be a number of misconceptions, but I figure they'll clarify what I exactly don't understand. I think a lot of the...

Hello, I don't seem to know how to ask google this question so I thought I'd see if I could get an answer from here. Say I have 400 measurements of some variable. I take a sliding window of 50 events and take the standard deviation of each set of 50 events. That would be 350 measurements. Now...

Hi folks, I have a rather simple question on error propagation - I have 2 sets of models, where the results from model are used as variables in the next model. I need to know how to carry forward errors from one to another. Case - Model 1: Y = a*exp(b*X) + c The errors on X (which is a...

In my lab I have a TEM00 laser, so there is no electric or magnetic field in the direction of propagation (call it z direction). However, I know that the intensity of the laser is greatest when my eye is along z direction...why? If there is no electric field along this direction, then what is...

At what speed does a change in a static electric field propagate through a medium? I understand that through a vacuum it's the speed of light, but through a medium such as a conductor or insulator how fast will this change propagate? In classical electrodynamics, how do we model the...

Homework Statement A 200 MHz signal is to be transmitted over a point-to-point wireless link. Assume the earth’s surface is flat over the entire propagation distance, and is 700 metres above sea level. The transmitter is at ground level, and the receiver is situated on top of a multi-storey...

A few weeks ago I accidentally dropped my droid on some concrete :) Impact location was near the top center, slightly offset. I notice that an initial crack propagated downward about 1 in before making a perpendicular split. Each side of the crack continued along the phone glass heading towards...

Hello everyone. I'm really struggling to simulate a cavity problem. My goal is to be able to know what's going to happen if i introduce spatially dependent phase inbetween mirrors of a cavity that supports certain transverse modes. Well, i believe solving for eigenmodes of a cavity is...

If I understand correctly in refraction, photon absorption and re-emission accounts for light taking "longer" to travel. Regarding Permeability and Permittivity, the below linked website states: "permittivity affects the speed of propagation of a wave through a medium"...

Need help propagating the uncertainty of Es = Ex ×(x+xo/xs+xo) . I understand all of the rules and can do it for a formula such as vo+ at. But I am having trouble with the (A+B)(/A+C)

Need help propagating the uncertainty of Es = Ex ×(x+xo/xs+xo) . I understand all of the rules and can do it for a formula such as vo+ at. But I am having trouble with the (A+B)(/A+C).

Whats the effect of shrinking and stretching of space on the propagation speed of electromagnetic waves. This is in reference to the direct correlation of the propagation speed to the fundamental properties of empty space viz. permittivity and permeability of free space. Do the permittivity and...

I read that for a plane wave E, B and k are always perpendicular to each other but then in a TM mode I have electric field in the direction of propagation. This means this TM and TE modes I cannot have in free space? Can I have them in a laser? If I can have some E-field in the direction of...

hi pf, i have been trying to understand since last few weeks how electromagnetic waves, say light travels? Not the way transverse waves do. It must require a medium. Then in vacuum how light travels? you may answer that with oscillating electric fields and magnetic fields at perpendicular to...

Dear all, I am a newbie in electromagnetic wave. Can you educate me, what will happen when an electromagnetic wave is blocked by a piece of flat metal placed in front of it? My intention is to build a thermal chuck using peltier for to measure femto amps from my device. I am worried if...

Hi, say I measure something ten times and get x+d1x, x+dx2, ... where dx1, dx2.. are the measurement errors. Now, say I want to calculate something from these measurements according to: A = B(C(x)), Where A is what I want, and B and C are known functions. Which is statistically...

I performed an experiment using different wavelength lasers to calculate the distance between the pits of a DVD by measuring the angles formed by the resulting diffraction pattern,but now I'm unsure on how to calculate the uncertainty of the final result. I took 9 measurements each with their...

Is there a simple way I can measure the propagation delay of my logic gates? For instance, is there a circuit I can build (using logic gates) to measure the propagation delay? What if I tried building a circuit whose output constantly oscillates? This would certainly prove that the...

I'm writing up an experiment I did for a lab course and I am calculating the error in quantity V. I have two runs and have ended up with a value of V for each one, as well as an error. Ie, I have V = 0.1145±0.0136 for Run 1 V= 0.1146± 0.0134 for Run 2 I got my errors through some tedious...

Homework Statement I slide a ball off of a ramp (the ramp is on a table) and the ball hits the ground and bounces horizontally and vertical. I know that horizontal velocity = horizontal distance*sqrt(gravity/2*height) or d*sqrt(g/2h) I want to know the equation for calculation error. The...

Homework Statement A lighthouse emits a noise with a frequency of 2000 Hz in the direction of the sea, with a power of 100W. Consider the speed of sound, vs, to be 341 m/s. A ship approaches the coast with a speed of 30 km/h and produces noise with an intensity of 40dB. Consider it is...