Phase Definition and 1000 Threads

When a substance undergoes a phase change from a solid to a liquid the substance can absorb heat energy without undergoing a temperature change. But I also read that when a substance melts, the atoms absorb energy and thereby vibrate faster, overcoming the intermolecular forces. Temperature is...

Imagine that an excited hydrogen atom in the symmetric 2s state emits a photon. We use a birefringent crystal to split the photon into vertical and horizontal components. Is the phase relation between these components random or is it the same for every photon emitted by a similarly excited...

Homework Statement Three load each having a resistance of 16 ohms and an inductive reactance of 12 ohms are wye connected to a 240V three phase supply. Determine: a) the impedance per phase b) the current per phase c) the kVA total d) the Power Factor e) the kW total Homework...

3 PHASE INDUCTION MOTOR A 15 hp/230V, three phase induction motor has a full load current of 42A per terminal. 15HP= 11kW find: a) Full load kVA input b) If the full load power factor is lagging 0.85, what is the kW input. My question: How do I know whether its connected Wye or Delta?a) kVA=...

Is there any relationship between phase space and entropy? regarding to decay of particles

I am doing project on open loop v/f control of three phase induction motor. How to decide the frequency and amplitude of triangular wave(carrier wave) for sinusoidal PWM ?

Homework Statement A man is sitting between two speakers, 5 meters from the first and 6.5 meters away from the second. Speaker 1~~~~~~(6.5m) ~~~~~~ Man ~~~~ (5m) ~~~~ Speaker 2 They both create sound waves in phase. What's the lowest frequency for which the man hears both sounds in phase...

So for the phase velocity of a massive particle we have Vph = Vg/2 for non-relativistic case Vph = c^2/Vg for the relativistic case Vg is the group velocity or particle velocity But there seems to be a contradiction in that for the non-relativistic case the phase velocity is...

i am looking for the amplitude ratio and phase shift of this graph? could someone explain me how to obtain these results from this type of graph? thank you

Homework Statement A simple harmonic oscillator consists of a block of mass 2.00 kg attached to a spring of spring constant 100 N/m.When t
=1.00 s, the position and velocity of the block are x = 0.129 m and v
= 3.415 m/s. (a) What is the amplitude of the oscillations? What were the (b)...

I am having some trouble fully understanding the basics and I just wanted to see if somebody would please clarify this for me. First, say you have a one component system in two phases: vapor and liquid. Gibbs' phase rule restricts the system to one independent, intensive variable that may be...

Homework Statement I've been asked to estimate ωn and ζ from the magnitude and phase plot of an atomic force microscope. The magnitude and phase plot is attached. Does anyone know how to solve for these values?

As a material is heated, it increases in temperature until it enters a phase transition. During the transition, added heat does not increase the temperature. As this heat is being added, what is the substance? Is it a mixture of liquid and gas perhaps? If so, what are the proportions? In...

Is it possible for a surface to be obtained as the solution for a system of differential equations in a 3d phase space? Almost all 3d phase plots I have observed are curves,example the Lorenz system. Is there a general formula that says that a system of n differential equations would...

In Weinberg's textbook on QFT(google book preview), he discussed the phase acquired after interchanging particle labels in the last paragraph of page 171 and the footnote of page 172. It seems he's suggesting interchanging particles of same species but different spin states will only bring a...

I have indirectly sought the answer to this for some time (since I studied an introductory course in optics 'long' ago), but nobody has been able to give a satisfactory answer, and I have not been able to find the exact answer on the Internet either. My question is about optics, and more...

I have a question and am wondering if reddit can help. In a 3 phase power system, the overall total power is meant to remain constant. Now, I understand that the individual powers are meant to vary, but as a system, it is supposed to be a constant. If you could take a look at this "code" if you...

The Hpyerphysics site, while discussing coherent light of lasers, says that… “the emitted photons are "in step" and have a definite phase relation to each other.” So now I wonder about electrons of an atom absorbing photons. Assuming the correct energy level for a given photon, is the...

Homework Statement Its part B ii) and iii) that I'm stuck on.Homework Equations Apparently for stationary waves, the phase difference between two particles = m(pi), where m is the number of nodes between the particles. This is according to my textbook here: The Attempt at a Solution So...

Let's consider a single frequency signal of frequency say 'f'. If the wave is propagating through a medium (EM wave with a velocity of 'c') then what will be the phase and group velocity? I believe that we can't find out the phase velocity and that the group velocity should be equal to the...

According to wiki- For surface gravity waves, the water particle velocities are much smaller than the phase velocity, in most cases. Then have shown this diagram http://en.wikipedia.org/wiki/File:Wave_group.gif How is particle velocity of a wave related with the phase velocity of the...

Hello. To give some more information on what I am to use this for: I have two signals. Both are periodic sine waves with the same frequency, but with a constant phase difference. Let's call one of the signals for ref (reference) and the other sig (signal). They can look like this: ref(t)...

An observer stands 3 m from speaker A and 4 m from speaker B. Both speakers, oscillating in phase, produce 170 Hz waves. The speed of sound in air is 340 m/s. What is the phase difference (in radians) between the waves from A and B at the observer’s location, point P? And I have no idea how...

It's common to express phase differences between two sinusoidal waveforms as a "phase angle", with a full cycle corresponding to 360 degrees. What is the origin of this nomenclature, and why is phase expressed in degrees? Examined naively, the time domain representation of two waveforms...

Homework Statement See attached image Homework Equations Δphi = 2pi(Δx/λ) + Δphi0 = 2pi(m) -- at the maximum Δphi = (m + .5) (2pi) -- at the minimum The Attempt at a Solution The first step should be to solve for lambda, the wavelength. So I plug in the knowns: At 30 cm...

Dear ForumersI am having a bit problem understanding the phase relation between current source and the generated eletromagnetic field components. Assume a very small current element( a very small current running in direction x)(essentially an electric dipole) in a non-homogenous loss periodic...

In single phase series circuits, should the current always be drawn along the x-axis and the voltage then drawn with respect to it? E.g. Should Vr be drawn in line with I, VL leading by 90 degrees (pointing upwards) and Vc lagging by 90 (Pointing down)? The reason I ask is because I've seen...

I have been given the following problem: How much heat is needed to change 50.0g of water at 80.0°C to steam at 110°C? The equations that I have used are the following: [SIZE="2"]Q = mCΔT [SIZE="2"]Q = mL I've set up my equation as such: [SIZE="2"]Q = mCΔT + mL However, I...

Homework Statement So my thermo professor has been putting a huge emphasis on phase diagrams, which I didn't really expect. He basically skips most of the analytical/calculus type problems and gives us the graphical phase diagram/ "real world" type of problems for homework. I don't...

Homework Statement Atomic losses can be described in the Lorentz model by adding into the equation of motion a damping term proportional to velocity. The equation of motion is then \partial ^2x(t) / \partial t^2 + \gamma \partial x(t) / \partial t + \omega_o^2 x(t) = qE/m Consider the optical...

Homework Statement H(e^jw) = (1-1.25e^(-jw))/(1-0.8e^(-jw)) Prove |H(e^jw)|^2 = G^2, and what is G Find Magnitude & Phase Homework Equations H(e^jw) = (e^(jw)-1.25)/(e^(jw)-0.8) H(e^jw) = 1 - (0.45e^(-jw))/(1-0.8e^(-jw)) H(e^jw) = 1 - 0.45/(e^(jw)-0.8) The Attempt at a...

Homework Statement This is part of the derivation of the direction of rotation of an ellipse in EM wave polarization. I need to find the direction of the change of phase \psi of the electric field vector with increase of time t. To make the long story short, for example: \psi\;=\...

The question is as follows: A point source emits a spherical wave with λ = 500 nm. If an observer is far away from the source and is only interacting with the light across a small area, one can approximate the local wave as a plane wave. How far from the source must the observer be so that...

ok, I would just like to know in general b/c we have to do this a lot. The equations have the same amplitude, but different k and w suppose you have y1 = Asin(k1x-w1t) and y2 = Asin(k2-w2t) and only other information is they are on a string, at a point x, and a time t. side note...

Hi, In the equation y(x,t) = ym * sin(kx - wt - PHI) I thought I understand why we have that phase constant atleast mathmetically but after thinking about it I don't think I understand it completely like here in my book it says the phase constant moves the wave forward or backward in...

Homework Statement Two loudspeakers emit sound waves along the x-axis. a listener in front of both speakers hears a maximum sound intensity when speaker 2 is at the origin and speaker 1 is at x=0.50m. If speaker 1 is slowly moved forward, the sound intensity decreases and then increases...

Hi All, Good morning. we had a 20MW, 13.8 KV wye generator and it has a neutral grounding resistor. Some how we failed to connect the neutral grounding resistor and during a rain storm we burnt the generator. Even though the neutral is not connected to the neutral grounding resistor it was...

we have the wave equation as follows with non zero phase constant: y(x,t) = ym * sin(k( x - PHI/k) - wt) or y(x,t) = ym * sin(kx - w(t + PHI / w)) I don't understand where did the PHI /k or PHI / w came from ?? I understand how did we derive the wave equation but I don't...

1. A coil connected to a 230V 50Hz supply takes a current of 10A at a phase angle of 30o Calculate the resistance and inductance of the coil 2. i = ImSinωt, R=V/I and XL=2∏fL 3. To get the resistance I used the value of 10A to get the value of Imby dividing 10 by sin30 which = 20A...

Let’s assume I use an ideal rotary phase converter to power a three-phase 10HP motor (100% efficient, PF = 1). Thus, I need S = 10 VA. On a 120V single-phase line, I would get three-phase line-line voltages of 240V. Here’s my question. I was under the assumption that when you analyze motors...

A sine wave traveling in [SIZE="4"]+x direction can be represented by \cos(\omega {t}- kx+\phi). As shown in the drawing attached where \phi=\frac{\pi}{2}: [SIZE="4"]a) Is a plot that holds t=0 and two waves along +x direction. t=0\Rightarrow\; \cos(\omega {t}- kx+\phi)\;=\;\cos(-...

What is the meaning of phase, S in Bohm theory? Is it same as the action in classical 1? What is their different?

Homework Statement A classical gas consists of N molecules; each molecule is composed of two atoms connected by a spring. Identify the dimensionality of the phase space that can be used to describe a microstate of the system. The Attempt at a Solution I believe the answer is 12, but...

Hello I am designing single phase inverter with TMS320LF2406 DSP. I created sinusoidal output voltage, and now i want to make regulation. While reading about regulation i found that it is recommended to use outer loop as voltage loop to generate Iref using PI controller, then this Iref...

Hi My 2'nd year of engineering doesn't quite let me to find an answer to the following problem: In a nutshell: I want to use rankine cycle to extract 5kW worth of electrical energy from a system utilizing R134a as working fluid. The properies of R134a are as follows: Tag R134a...

Hi, What does d-BCT phase signify in crystalography?

This is about a specific property of the Wigner distribution in phase space. My professor mentioned the other day that the Wigner distribution treats all functions of momentum and space on the same footing as momentum itself or at least that's what I recall.He mentioned a specific problem where...

Let's focus specifically on AC circuits and a mass on a spring since those are the types of SHM I know. Does the phase relationship matter? For instance, with a mass on a spring, position and velocity are 90 degrees out of phase. But does it matter to say which leads the other? After all...

I just watched a video of James Gates and he discussed something he called the Gross Perrywall phase transition. It was named after David Gross, I am assuming most of you are familiar with his work. In an attempt to search more about this I came up empty. I do not know if I am spelling it...

I had been wondering if this were possible for a long time. While working on my MS thesis at school, I learned about Phase Locked Loops for the first time. It took me weeks of curling up at night with H.&H. The Art of Electronics for me to even get the concept. I had never heard of a Bode plot...