Phase Definition and 1000 Threads

A mate of mine has bought a Pramac GSL30 generator (30kVA) ‘as seen’, and of course there is no output. Inside the connection box of the Stamford alternator unit, someone has been fiddling - the output wires have been disconnected and taped, and the AVR has also been unplugged. Now, it’s a...

I couldn't get a good explanation differentiating phase and grain.From what I understood, a collection of unit cells arranged in the same orientation is called grain.A collection of grains with similar structure is called phase.Is this interpretation right?

Homework Statement Prove the following relation for which clausius equation holds : Cs=Cp-αV(ΔH/ΔV) Where Cs=∂q/∂T at constant S and is the heat capacity in the coexistence line of 2 phases Homework Equations dq=dU+dW dP/dT=ΔH/(ΔV*T) The Attempt at a Solution I do not fully understand why q...

Recently I read something in NASA Tech Briefs about an instrument that could measure phase differences as small as .001 degree in light. I would like to create an instrument that could do this for every pixel in a picture, even if it was only a few hundred pixels (such as a 20x30 pixel array)...

In the field of medical physics, specifically in monte carlo simulation of radiation beams produced by electron accelerators, people call ‘phase space’ to a file that contains the data of a large number of particles when they traverse a reference surface in the machine (usually a plane), i.e...

I am trying to calculate the increase in pressure caused by liquid nitrogen when it changes from liquid to vapor within a closed, constant volume at atmospheric pressure. How can this be done? Do I need to include the heat of vaporization?

What does a 180 degree phase shift of a sinusoidal in a signal do to the frequency spectrum of the signal?

I understand that a radio telescope can be tuned to receive radio waves generated by neutral hydrogen atoms present in galactic gas, for example, within the spirals of the milky way. I think I understand that the incoming radio waves will be a mixture of red- and blue-shifted photons depending...

Homework Statement The phase transition to a superconducting state moves to lower temperatures as the applied magnetic field, H, increases. The magnetic moment, M, for a system of volume V is given by: $$M=-\frac{HV}{4\pi}$$ for ##H<H_C(T)## (superconducting) and $$M=0$$ ##H>H_C(T)## (normal)...

From classical EM theory, we know that if we shine light of frequency ω on a second order non-linear medium, a radiation of frequency 2ω is created. The amplitude of the radiation of frequency 2ω is dependent on the momentum difference between the incident field and the created field. But I...

Homework Statement From Classical Mechanics, Gregory, in the chapter on Hamilton's equations of motion: 14.13: Decide if the energy surfaces in phase space are bounded for the following cases: i.) The two-body gravitation problem with E<0 ii.) The two-body gravitation problem viewed from the...

I have a question with regard to split single phase (in United States) electricity. I understand that there are 2 hot legs each 180 degrees out of phase at +120v and -120v (240v between hot legs) going from transformer to breaker box and a center tapped neutral Earth bonded wire at 0v with...

In binary phase diagram, We draw a tie line to know the composition of the liquid phase or the solid phase. Where the tie line is just a horizontal line. The question is why doesn't the liquid or solid phase composition change as you change the general composition of the alloy? Why does the...

Homework Statement State the amplitude, period, phase shift, and vertical shift: ##y=\frac{5}{2}sec\left(\frac{π}{x}-4π\right)-2## Homework EquationsThe Attempt at a Solution [/B] Amplitude: Amplitude is equal to the absolute value of a. So the amplitude here is ##\frac{5}{2}## Vertical...

Hello, I am working on a project to calculate harmonic distortion on a mains signal. The signal has already been stepped down so it oscillates between 0-5V at 50Hz. I looked into some old THD analyzers and it seemed they would generate a clean signal to mimic the fundamental deduct this from the...

I am working on synthesis modelling of guitars, and I have managed to capture most elements of the guitar well so far. Something I am struggling to understand is why a guitar string has a natural "beating" sound to it, meaning it sounds as if it is ebbing and flowing slowly as it vibrates. To...

I have a MATLAB script for modelling a two tone signal (a sum of two sinusoids) going through a non linear transfer function (such as an amplifier). The amplitude of a signal is amplified non linearly, and also the phase is modified depending on the input power of the signal. The two sinusoids...

Homework Statement In a Newton's rings apparatus, find the phase difference (in radians) when an air wedge of 500nm thickness is illuminated with red light (lambda = 640nm). t = 500nm lambda = 640nm radians = degrees × pi / 180° Answer) 13 Homework Equations 2pi x path difference / lambda...

We know that reflected light undergo a phase shift of π in EXTERNAL REFLECTION but there is no phase shift in INTERNAL REFLECTION . Does this violate Stokes Relation, which states that every reflected beam undergo of phase shift of π ?

Hello, I am a student in Coventry, UK working on Phase Change Problems and going through 1-Phase Neumann Analytical solutions. As per most books, or specifically Mathematical Modeling of Melting and Freezing Processes chapter 2 (attached) page 36, equation 15, the general equation of...

Homework Statement So I have got the question below. I am asked to find the phase difference between the electric field and magnetic field of electromagnetic waves traveling in a plasma, using the electrical conductivity expression. Now I have found the frequency of the waves and I know that...

Homework Statement Homework Equations Asin(wt + Φ) The Attempt at a Solution let t = 0 Case A: -.10 = .20sin(Φ) sin-1(-.10/.20) = Φ = -0.52 Case B: .10 = .10sin(Φ) sin-1(.10/.10) = Φ = 1.57Case C: -.05 = .05sin(Φ) sin-1(-.05/.05) = Φ = -1.57Case D: 0 = .20sin(Φ) sin-1(0/.20) = Φ = 0 Now...

Homework Statement Q10.20 Using the isothermal transformation diagram for a 1.13 wt% C steel alloy (Figure 10.39), determine the final microstructure (in terms of just the microconstituents present) of a small specimen that has been subjected to the following time–temperature treatments. In...

At critical points, when correlation lengths diverge near a phase transition, people often say that the spectral gap closes, which is to my understanding just the energy difference between the ground state and the first excited state (the first two eigenvalues of the hamiltonian). How should we...

Homework Statement How can I calculate the initial phase in a simple harmonic motion if I only have the amplitude, frequency and angular velocity as data? Homework Equations The formula of the position, in fact they ask me to do the formula that allows to know the elongation depending on the...

Long time no see, PhysicsForums. Nevertheless, I have gotten myself into a statistical mechanics class where the prof is pretty brutal and while I can usually manage, this problem finally has me stumped. I'd like to be nudged in the right direction, not outright given the answer if possible. I...

Homework Statement The Attempt at a Solution I am having trouble visualizing this. So I know that the phase margin is how much phase lag it would take to make -180 phase at the 0 dB gain frequency. I am just having trouble placing this on the plot. It isn't a homework question I am preparing...

Hello all; I am trying to calculate leakage reactance of three phase power transformer . I am using Ansys Maxwell final element solution to analyse it. The software gives me total energy and linkages and self and mutual inductances.By using this quantities how can ı compute leankage reactances...

Hi all I have simultaneously recorded data coming from three pre-amplifiers with same input applied to these pre-amps. After post analysis, i found that there are phase and gain differences among these outputs ( which should be zero in ideal case). I set one preamplifer output as reference and...

I'm having trouble understanding the phase shift produced by a beam splitter. I seem to be finding conflicting information. I'm specifically looking to understand a 50/50 beam splitter where one side has a dielectric mirror, as shown in this figure from wikipedia: I understand the pi...

Hello, I would like to know, why is the volume of gas produced during phase change significantly more than the original volume of the liquid being used? Say water changing phase at 1atm.

Homework Statement I am working through problem #1, a-c. Homework Equations The main equations are dx/dt=Ax, (A-rI)v=0, and det(A-rI)=0. The Attempt at a Solution [/B] Here is my attempt. I am fairly confident in my answer to A. I'm less sure on my answer to B, however it is the same as...

A couple of months ago I was troubleshooting a blown fuse on a power factor correction capacitor in a 4160v motor starter. While I was working through it I noticed that my DMM (fluke 289) would charge the capacitor to a certain degree while on the Ω function. The current from the meter would...

I am currently designing a three phase permanent magnet axial flux generator, but have a question regarding the voltage induced in the copper coils. Faraday's law defines this voltage as the number of turns in the coil, times the change in flux (external magnetic field times area of coil) over...

How is the phase difference between the current in the primary coil and induced e.m.f. in the secondary coil be 90*??

Homework Statement Assume that the two balanced loads are supplied by an 840-V rms 60-Hz line. Load #1: Y-connected with 30+j40 Ω per phase, Load #2: balanced three-phase motor drawing 48 kW at a power factor of 0.8 lagging. Assuming abc sequence, calculate the complex power absorbed by the...

My textbook (Serway and Jewett, Physics for Scientists and Engineers) says that Emax/Bmax = E/B = c. And that E and B are in phase. My question is, if they are in phase, they both reach zero at the same time. At that point, E/B = 0/0 and not c. I know I am missing something, but not sure what...

I was vacuuming my house, the vacuum cleaner is 1600w rated I remember, then i unplugged the cord from wall socket and I observed something interesting , and to be honest I remember I have seen this before with my washing machine and elsewhere, when I take out the plug from the wall socket I...

Homework Statement apparently your effective power is V_maxI_max * cos(x) where x is the phase angle. So I must consider only real power Homework Equations power = VI current = I sin(wt) The Attempt at a Solution Let impedence be = e^ix . I'll write current as Ie^i(wt) consideronly the real...

If a photon doesn't travel through time (if there is no internal change by one definition of time) then I would expect a photon not to have a changing phase as that seems to count as a timeable internal change. Is this the case?

Hi all Decided to post in 'beyond standard model' because lattice gauge theories are usually used to explore these models. Hope that's all right. So in lattice simulations, phase transitions in beta mass plane seem to have an important meaning. I understand phase transitions from a...

my transformer book does not cover an area i am interested in and was wondering if someone would direct me to literature that would help me understand something and if you wouldn't mind trying to explain it to me yourself that would also be appreciated. you have three single phase transformers...

Today I took two coils and connected one of them (coil A) to an AC power supply. I held the second coil (coil B) close to the first one and then connected them both to a dual trace CRO. As expected, an emf was induced in coil B and the traces on the scope were 90 degrees out of phase. As I...

Homework Statement Homework Equations Three phase half controlled bridge rectifier can have 3 pules at output or 6 pulses depending on firing angle. The Attempt at a Solution Ripple frequency is m times the input frequency where m is number of pulses. It can be 3 or 6. So why have they...

I am pretty sure that I would be comparing apples and oranges in this question, but as I usually learn something from the responses telling me in detail that my question is silly, here goes: Does the phase used as a weight in Feynman's path integral formulation (i.e., the quantum action S in...

I am stuck trying to derive the unwrapped phase function of a Fourier Transform. Here is the gist of the derivation. We can express the Fourier Transform in polar form: X(e jω) = |X(ejω)| ejω We can take the ln of both sides, resulting in: ln X(ejω) = ln | X(ejω) | + j θ(ω) Taking the...

Am I trying to solve a simple equation, but get stuck at the basic. I have have a spring with a cube attached to it (1kg). When I pull it with 5N, the spring extends to 50mm =amplitude, (Hooks law) the koefitient is 120. The determined absortion coeffitient is 0,2^-1s. I tried to get the...

Homework Statement From the phase diagram what can be said of the porosity, mechanical strength, and density of various materials in the diagram? Homework EquationsThe Attempt at a Solution I am having trouble finding research on the general properties of quartz, feldspaar, and clay mineral...

Homework Statement Question 2 Homework Equations Flux time lag depends on L/R ratio. More resistance, less time lag. Single Phase IM---Double Revolving field theory The Attempt at a Solution For 1st question, I think answer should be A. BB circuit has more resistance so BB Flux will have...

Homework Statement Homework Equations For Delta line current = 1.732 times phase current. Line voltage = phase voltage The Attempt at a Solution I don't know how to start this. This is original connection This is new one The voltage should be 3 times because of additive polarity. Not sure...