Phase Definition and 1000 Threads

  1. AwesomeTrains

    I Help understanding the formula for the total phase shift of a waveplate stack

    I have problems deriving a formula in a paper I'm reading for a project. The paper is about putting a number of waveplates in series rotated relatively to each other to form a tuneable broadband waveplate. For the i-th waveplate the jones matrix is given by: $$ J_{i}(\delta_i, \Theta_i)=...
  2. D

    US 2-phase conversion to EU one phase

    I recently bought a machine from china. The power requirements are 220v single phase with 4 motors that draw about 16A collectively. The factory told me 5.5KVA as a minimum power source. If I use a step up transformer from 120v this means 45A max current draw. US 220v(240v) is really 2-phase...
  3. A

    Relationship between k and orbital phase of solid state?

    I understand that quantum objects have wave and particle properties. I know that k = 2π / lamda. I am simply not understanding the x-axis of a bandstructure plot of E(k) vs. k. I've read parts of a book by Roald Hoffman on this subject. In the book it is shown that there are infinite chain of...
  4. Peter McBride

    AC Single phase stator wiring help

    This stator is out of a Wisconsin VG4D gas motor. Both black leads go to a rectifier. Red and white leads go to a regulator. White lead pigtail goes to ammeter gauge and on to battery. I need to rewind but for the life of me I can't figure out how to connect the winding to the 4 leads coming...
  5. A

    Understanding Polarization-Dependent Phase Shifts of Radio Waves

    I've seen this video: There it is explained that an electromagnetic (here radio) wave has a phase shift if it was radiated in horizontal polarization, but it does not experience the phase shift when it was emitted vertically polarized when it gets reflected on the ground. When reading up on...
  6. MedEx

    Find the Driving frequency and phase angle for this R-C phasor problem

    Using the givens I found ωd=862 rad/s, and with some help I got tanϕ=-1 and Z=56.5685 ohms. But I can't figure out any of the other variables. I'm not even exactly sure what "driving frequency" is and I can't find an equation for it.
  7. M

    Coil and resistor in parallel -- How to calculate the phase angle?

    Hello. So I have a coil and a resistor in parallel connection. It is powered by alternating current. I have to calculate angle between voltage and current, what is the formula? I know the reactive resistance in coil, I know resistance of resistor, voltage across both of them and amps flowing...
  8. Adgorn

    Rayleigh criterion when light phase is known

    Hi everyone, this is sort of a soft question which I need to ask to make sure my understanding is correct, it relates to a little project I'm doing on measurement resolution. The first question is to clear up a general concept, the second is based on the first and is the actual question...
  9. Q

    B 'IdealFluid' Describe Behavior of Matter in Phase State of liquid/gas+

    One thing about terminology that I think c/should be changed for Continuum Mechanics: 1) 'Ideal Fluid' Describe Behavior of Matter in Phase States of liquid/gas and sometimes Bulk-Solid: -continually deform under applied shear stress or external force -usually zero shear modulus -behavior can...
  10. J

    A Is the cluster decomposition equivalent to no phase transitions?

    I think the cluster decomposition states that products of space like separated observable decouple when sandwiched with states. An analogy with statistical mechanics seems to suggest that we are stating there are no phase transitions. For example, in the Ising model all spins are correlated in...
  11. A

    Enhancing the thermal conductivity of Phase changing materials

    A) What are the modern techniques used for enhancing the thermal conductivity of Phase changing materials (PCM) ? B) what are the negative effects (disadvantages) of using old methods of enhancing thermal conductivity of PCM ? ( construct table ) C) what are the different techniques used for...
  12. E

    Line voltage in 3 phase as single sine wave

    Howdy all. The typical image of a three phase electrical system involves 3 sine waves, phase shifted 120 degrees. These sine waves each, individually, represent the 'phase voltage,' which is to a common neutral in a wye configuration. In this wye configuration the line to line voltage is...
  13. yecko

    Understanding Load kVA and Power Factor in Three Phase Transformers

    For question 2.28, the load kVA requires the use of power factor before calculating the line current, while eg 2.7 do not. May I ask why do they have the difference of using PF or not? Thank you.
  14. W

    Find the amount of ethanol (70 degC) in gas phase in a tank at atm

    I first found the partial pressure of ethanol at 70 degrees using Antoine coefficients: Coefficients: A 7.68117 B 1332.04 C 199.2 Equation: And found a partial pressure of 0.7 bar...
  15. C

    How does specific volume play its role in the phase diagram?

    So, I am casually sifting through a chapter in a thermodynamics textbook talking about the multiphase process that pure substances go through. I understand how the P-v and T-v diagram works and that out of the three properties (specific volume, temperature and pressure), two of them are...
  16. F

    Phase difference between sound waves

    I had to find the phase difference between sound waves created by two sources at different distances from a given point. I found the correct answer to be about 13.4. Would any other answer of the form (13.4 + 2npi) also be correct, assuming n is a non-zero integer? Or is 13.4 the only correct...
  17. Spinnor

    B Phase change or not: oil in the refrigerator

    Cooked some french fries last night using oil saved in the refrigerator. The oil appears to have undergone a phase change, after some time in the refrigerator instead of being a yellowish transparent liquid it was a semi-solid soft whitish non-transparent stuff when I took it out of the...
  18. P

    Unbalanced 3 phase power - what happens without a neutral wire?

    Hi I've recently started learning about electrical three phase theory, and therefore got some questions. Imagine the following: Countries like Albania, Norway ++, have IT earthing configuration in their distribution grids, i.e. the neutral point is not solidly grounded, however "grounded"...
  19. K

    Required voltage for this large saw (German three phase schematic)

    Hi.. I am trying to figure out the required voltage for an Austrian built saw. I am not very good with AC plus the schematics are in German, I think, which is further confusing the matter. Here is the saw: http:/altpubad.com/Temp/1265-1994.pdf I assume it uses three 240 lines but thought I...
  20. L

    How to introduce a phase shift in an AC circuit

    Hello, I am trying to think of a way to introduce a phase shift in an ac circuit. For example, sin(omega*t+theta) to change theta. How can I go about doing this? I do not think introducing a cap or inductor would work, even though it shifts the voltage from the current graphs (phasors). A...
  21. IshaanM8

    Question about Phase Change & Latent Heat

    Homework Statement When running, some (heat) energy is lost by the evaporation of sweat. If a runner loses 1.0 MJ( Mega Joules) of energy via sweating, calculate an approximate mass of sweat evaporated from the runner. Homework Equations Q = McΔT Q (Joules) = M (Mass) c (Maximum Heat...
  22. Z

    Trouble solving an ODE and plotting its phase portrait

    Mentor note: Moved from non-homework forum to here hence no template. So I was able to solve part 1.A of the first problem by hand, the phase portrait is a sideways parabola. However, I want to also show on this on mathematica. I want to solve the equation first and then plot the phase...
  23. B

    I Phase shift after double-slit for entangled photons

    Hi all, I'm trying to understand how to describe the quantum state of entangled photons, including their phase, if one of them encounters a double-slit. Here's a simple example: Suppose you have two polarization-entangled photons A and B in the following Bell state: \begin{equation}...
  24. S

    Phase difference between points on wall

    Homework Statement Parallel water waves of wavelength 10 m strike a straight sea wall. The wavefronts make an angle 30o with the wall. What is the difference in phases between the waves at two points 5 m apart along the wall? a. 30o b. 45o c. 90o d. 156o e. 180o Homework Equations Δφ = Δx / λ...
  25. Mohamed_Wael

    Moving Mesh vs three phase field flow (Comsol)

    I really don’t understand the advantage of 3 phase flow, phase field module in comsol. For example, if I want to simulate a compound droplet inside a fluid. Can’t I use the moving mesh with 2 fluid-fluid interface? If yes. When should I use the 3-phase flow, phase field simulation?
  26. iVenky

    I Why high Q factors have low phase noise

    If we define Q factor as 2*pi* energy stored/ energy dissipated per cycle, what's the physical insight behind obtaining low phase noise for oscillators when we have high Q factors? (I know the mathematical derivation based on finding the frequency profile of an oscillator (like LC oscillator)...
  27. P

    I Why is the Phase Shift in Grover's Algorithm Applied to All Elements Except 0?

    Hi everybody, I've read some pages in Nielsens "Quantum Computing" book, it's very interesting, but especially at Grover's algorithm, there occurs a question for me. It is said that a phase shift is performed, which is defined as follows: ##|0\rangle \rightarrow |0\rangle \\ |x\rangle...
  28. A

    Phase space trajectories can't intersect...

    Phase space trajectories can't intersect each other is it due to the fact that at the intersection point there will be more than one possible path for the system to evolve with time??
  29. MattIverson

    What are phase space coordinates and how do you plot them?

    Homework Statement I have phase space coordinates (x0,y0,z0,vx,vy,vz)=(1,0,0,0,1,0). I need to analytically show that these phase space coordinates correspond to a circular orbit. Homework Equations r=sqrt(x^2+y^2+z^2) maybe? The Attempt at a Solution My core problem here is maybe that I...
  30. T

    Difference in Wave Phase Question

    Homework Statement A. Two identical speakers, with the same phase constant, are arranged along a 1D track. One speaker remains at the origin. The other speaker can slide along the track to any position x. You are on the track at x=10 m. You hear interference maxima when the adjutable...
  31. S

    Understanding FLP Vol 1, Section 30.1: Struggling w/Magnitude & Phase

    I’m having trouble understanding section 30.1 of FLP Vol 1. Particularly the first figure is causing me struggle. I understand magnitude and phase, such as fig 29-9 when 2 waves are added to get an effective resultant vector. But I’m struggling to see how equation 30.3 is applicable when it’s...
  32. Talisman

    I Mirrors, phase shifts, and position

    I'm confused about something regarding phase shifts but I'm not sure I've pinned down what. I had always thought of a mirror as introducing a global phase shift of π in the position basis, but I only now realize that this makes no sense: of course -A ⊗ B = A ⊗ -B, so a global phase shift is not...
  33. C

    How does the phase noise of the LO effect IF accuracy?

    Hi, I have a roughly 1.1 GHz signal to be downconverted to 100 MHz by mixing it with a 1 GHz local oscillator. I am not sure how to choose the performance of the LO. In particular: let's assume the LO has a jitter of 100 fs rms. At 1 GHz this corresponds to a frequency error of 100 kHz. Does...
  34. QuasarBoy543298

    I Volume in phase space- Louviles theorem

    I was looking at the following proof of Louviles theorem : we define a velocity field as V=(dpi/dt, dqi/dt). using Hamilton equations we find that div(V)=0. using continuity equation we find that the volume doesn't change. I couldn't figure out the following : 1- the whole point was to show...
  35. H

    I Phase and group velocity for a free particle

    Why for the free particle, the group velocity and phase velocity are not the same while we have only one wave? What is the envelope here?
  36. E

    Phase relation between strain and particle velocity

    I'm trying to understand the following derivation. Starting with the one-dimensional equation for a traveling wave ##u = u_0 \exp{[j(\omega t - \beta z)]}## the goal is to derive the phase relation between strain and velocity. The author first derives the relationship between strain and particle...
  37. cookiemnstr510510

    Reading a Binary Phase Diagram (lever rule etc.)

    Hello All, Wanted to see if I am approaching this problem correctly, I have an exam coming up and am pretty sure something like this will show up. Examine the phase diagram (phase.jpg) with a 20WT% A and 80WT%B which is allowed to cool slowly from liquid A) what temp does the first solid...
  38. DracoMalfoy

    Thermal physics phase change: Liquid copper to solid

    Homework Statement How much energy must be removed from the system to turn liquid copper of mass 1.5kg at 1083 degrees celsius to solid copper at 1000 degrees celsius? a. -2.49X10^5J b. -3.67X10^4J c. 2.25X10^3J d. 9.45X10^4J e. -2.78X10^3J Homework Equations Q=Mc(Tf-Ti)...
  39. zehkari

    How to Find y in a Double Slit Experiment Without Intensity Values?

    Homework Statement Homework Equations (1) Φ = 2π*(dsinθ/λ) (2) Itotal = I0 cos2(Φ/2) (3) Itotal = I0 cos2(πdy/λR) λ = 585 * 10-9 m R = 0.700 m d = 0.320 * 10-3 m y = ? The Attempt at a Solution a) I used eqn (1) and divided the total oscillations by a complete oscillation to find the...
  40. N

    A Phase transition under pressure?

    hello everybody does always phase undergoes transition when a pressure applied on a crystal ?even when the temperature is constant? and can pressure be increased without increasing temperature for a crystal? best regards Nawzad
  41. G

    Barton's pendulum, phase relationship

    Hi community, The phase relationship is 0 for the shorter pendulae, 1/4 cycle for the pendulum in resonance and in anti-phase for the longer pendulae; relative to the driver pendulum. I have observed this but I can see it conceptually to an extent but wondered if anyone knows of a resource for...
  42. L

    MATLAB Can I know the reconstruction of phase shift interferometry in Matlab

    I want to know the reconstruction of phase shift interferometry by angular spectrum method in matlab
  43. gasar8

    A Lorentz Invariant Phase Space: Symplectic Geometry

    I have an assignment to show that specific intensity over frequency cubed \frac{I}{\nu^3}, is Lorentz invariant and one of the main topics there is to show that the phase space is Lorentz invariant. I did it by following J. Goodman paper, but my professor wants me to show this in another way...
  44. Salman Ali

    Which of the options describes the phase constant for SHM?

    The only thing I know is that phase constant tells how much a signal is shifted along the x-axis. The answer of the question is both option a and b. I am not getting it!
  45. B

    Phase shift and circular polarization

    What is the phase difference between the right circularly polarized and left circularly polarized light of the same amplitude? And how do you calculate it?
  46. G

    Weak Damping - how to relate the amplitude and phase difference

    Homework Statement Derive the relationship bewteen x_{max}, A_{+}, A_{-} and \phi Homework Equations x(t) = e^{\gamma t}(A_{+}e^{i \omega_d t} + A_{-}e^{-i \omega_d t}) x(t) = x_{max} e^{\gamma t} cos(\omega_d t + \phi) The Attempt at a Solution I know the e^{\gamma t} cancels and for the...
  47. Y

    Phase angle and Phase in Simple harmonic motion

    I'm a teacher at a Senior High School in Indonesia. I have two Senior High School physics books (Indonesian book) written about simple harmonic motion formula: y = A sin θ = A sin (ωt + θ0) = A sin 2πφ = A sin 2π (t/T + θ0/2π) phase angle = θ = ωt + θ0 phase of wave = φ = t/T + θ0/2π But I...
  48. somasimple

    RedOx Reactions & Phase Changes

    Hi, In electro-chemical cells (galvanic, concentration, etc) or more generally when some RedOx reactions occur in solutes, is there always a phase change? I mean is there always a change in the state of matter from liquid to solid or gas?
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