Phase Definition and 1000 Threads

Hello, after I read in an exercise that the pressure inside of a spherical water drop is different than the pressure outside, I'm a little bit confused. Which is the pressure used in Gibb's phase rule and why don't the pressure change the form of the water drop?

Homework Statement (a) A transmission line has a length, ##l##, of 0.4λ. Determine the phase change, ##\beta l##, that occurs down the line. Homework Equations ##\beta=\frac{\omega}{f\lambda}## or ##\beta=\frac{2\pi}{\lambda}## The Attempt at a Solution This question was posted a couple of...

Homework Statement Let \begin{equation*} f(t) = 2 + \cos\left( 3t - \frac{\pi}{6} \right) + \frac{1}{4}\cos\left( \frac{1}{2}t + \frac{\pi}{3} \right) + \sin^2(t) \end{equation*} Determine the period ##T## and fundamental frequency ##\omega_0## of ##f## and draw images of its amplitude and...

Hi. I'm taking a look at some lectures by Charles Kane, and he uses this simple model of polyacetylene (1D chain of atoms with alternating bonds which give alternating hopping amplitudes) [view attached image]. There are two types of polyacetylene topologically inequivalent. They both give the...

Hi I have an engine that has three phase 18 pole stator for DC fired cdi system . I want to install it this engine in another bike frame the issue is that that frame has ac fired cdi wiring system. Where there is a special coil for the Ignition, lightning and charging. Can i covert the...

2. Relevant equation The Attempt at a Solution I can see straight away that the waves are 90 degrees out of phase so pie/2. But how is X ahead of Y? It looks like Y is ahead of X by pie/2.

Homework Statement For a balanced star connection i have given angles for V1=90 V2=0 V3=-90 i have to find the voltage required to produce the same phase currents as in standard three phase voltage source e.g V1=120 V2=0 V3 =-120 Homework EquationsThe Attempt at a Solution Im not even sure...

Hello! I was reading a paper on formulation of QM in phase space (https://arxiv.org/abs/physics/0405029) and I have some doubts related to chapter 5. It seems to me that there is a transformation to modified polar coordinates (instead of radius there is u which is square of radius multiplied by...

There is a question that has been bugging and puzzling me for a long time and I wondered if somebody could help me to figure out what the answer is or where I am not thinking straight. Let us assume that the standard model of particle physics is more "right" than "wrong" and there is no such a...

A friend has a ?40-50 kVA, 240 V, single phase generator, of 1970s vintage, coupled directly to an engine. It was working fine but now produces no power at all. All the brushes and spring holders are fine, as are the fuses. I can't find a decent description/diagram of the internals, other than...

I'm asking if space space is subject to change, if not, why not, and if so, then would it be subject to a subsequent phase space that describes that? Let us make a phase space for a deterministic time evolved dynamic system of three spatial dimensions. Since the actions of the system and the...

With sound you can create out of phase signals and they cancel out, this is not possible with light as it does not interact like sound does. If it was possible to create two light sources in that were exactly 180 degrees out of phase with each other and aim them at a common point (eg an...

Homework Statement 2. Homework Equations 3. The Attempt at a Solution [/B] For part (c), should the phasor diagram just have everything on a straight line, save for the Rt and Vrt? Honestly not sure how to attempt part (d) as we never really covered phase relationships in lectures, just...

If the single phase flows on the inclined surface and this phase (let's say water) is wetting the surface then closest layer to the surface will be bounded and will not move. And velocity of flow will be in inverse proportion with viscosity of the fluid. If now the second phase is introduced...

Homework Statement http://imgur.com/a/FDfAp What is the phase constant? Homework Equations x(t) = A*cos(ωt+Φ) The Attempt at a Solution If I'm not mistaken at t = 0 the graph starts at half the amplitude or 5. Also the amplitude of this graph is 10, and at t = 0 angular velocity is also 0. 5...

1. Homework Statement Find V2. Everything else is available in the picture Homework Equations r1=r1+a^2*r2 x1=x1+a^2*r2 z2=a^2*r2 I1=vp/z2+r1+x1 The Attempt at a Solution So I have used the first three formulas but it's the last one I am getting stuck on. Since my x1 is an imaginary number...

Homework Statement Consider the 3 following Scenarios: 1. 2. rms value of line voltage is 208 V Three equal impedances, 60 +j30 W each, are delta-connected to a 230-V rms, three-phase circuit. Another three equal impedances, 40 +j10 W are wye-connected across the same circuit at the same...

Hi, So I am aiming to derive the continuity equation using the fact that phase space points are not created/destroyed. So I am going to use the Leibiniz rule for integration extended to 3-d: ## d/dt \int\limits_{v(t)} F dv = \int\limits_{v(t)} \frac{\partial F}{\partial t} dV +...

Hi guys! I am wondering if someone can help me with an assigment i got, i would appreciate if someone could help me with it. Find effective value and phase shift for the current I in the link the tip is to use the superposition theorem http://imagizer.imageshack.us/a/img924/3673/R5qIAN.png

I am trying to create a phase sweeper at 31.4KHz(and constant 5V) for a small antenna array that consists 2 antennas. If I can create 2 signals with a frequency difference < 1Hz it's okay too(It will be nearly same) as long as I can control that difference because I need to change phase at a...

Homework Statement A 35 mH inductor with 1.0 resistance is connected in series to a 20 µF capacitor and a 60 Hz, 40-V (rms) source. Calculate the phase angle. Homework Equations tan φ = (XL - XC) / R The Attempt at a Solution Solving for φ: φ = tan -1 [(XL - XC) / R] XL = 2πfL = 13.194 Ω...

Homework Statement Two identical traveling waves, moving in the same direction, are out of phase by π/5.0 rad. What is the amplitude of the resultant wave in terms of the common amplitude ym of the two combining waves? (Give the answer as the ratio of the total amplitude to the common...

It is common to calculate Berry phases for quantum systems in, for example, a magnetic field. In this case we compute the Berry phase ##\gamma## using $$\gamma[C] = i\oint_C \! \langle n,t| \left( \vec{\nabla}_R |n,t\rangle \right)\,\cdot{d\vec{R}} \,$$ where ##R## parametrizes the cyclic...

For a time-dependent Hamiltonian, the Schrodinger equation is given by $$i\hbar\frac{\partial}{\partial t}|\alpha;t\rangle=H(t)|\alpha;t\rangle,$$ where the physical time-dependent state ##|\alpha;t\rangle## is given by $$|\alpha;t\rangle =...

Does there exist and analytical expression for the following integral? I\left(s,m_{1},m_{2},L\right)=\sum_{\boldsymbol{n}\in\mathbb{N}^{3}\backslash\left\{ \boldsymbol{0}\right\}...

Hello there, I want to write a fortran program which gives me the right ascension and declination of the sun and the phase of the moon when a date and time is given. I just want to know how to write it and if there are any references that can help me. Thanks, Jadaav.

There's something that I'd like to know and haven't been able to find in any book: 1.- Is the number of second order phase transition university classes known? 2.- Do we know quantitatively know the behavior of all such second order phase transition university classes? 3.- Do we know the...

I have a doubt regarding gibbs phase rule in thermodynamics.. It says the number of independent intensive properties required to specify the state of a system is F=C-P+2 where C is number of components and P is the number of phase.. So for a water and water vapour system, C=1, P=2 . So F=1. If...

If I had a container containing 10 bara of nitrogen, and pumped in liquid propane at room temperature would the propane boil? If I carried out the same experiment but this time at 5 bara, what would be the temperature of the material once the propane had completed its phase change i.e would it...

Homework Statement The two oscillators each have the same mass. Use Fig. 4.1 to determine (i) the phase difference between the two oscillators (picture attached) Homework Equations Subtracting to find the horizontal shift The Attempt at a Solution I found the two points where both graphs...

Gibbs phase rule says f = r-M+2 with f: thermodynamic degrees of freedom; r: number of components; M: number of phases I wonder whether the defintion of "phase" is restricted or almost arbitrary. For example, consider a system of H2O, O2 and H2 in a closed vessel. Let there be the contstraint...

If i have two sinusoidal ac signals of 220V with the different phase angle i.e. there is some phase difference between them. Then can i make the phase difference zero?? Please tell

Hi all, I hope this question is of an acceptable format to ask about here. I'm just having trouble trying to get a conceptual understanding of the following. I've been told that if I'm given two different frequencies that are completely in phase at time equal to zero, then I can find their...

Homework Statement [/B] (a) Verify explicitly the invariance of the volume element ##d\omega## of the phase space of a single particle under transformation from the Cartesian coordinates ##(x, y, z, p_x , p_y , p_z)## to the spherical polar coordinates ##(r, θ, φ, p_r , p_θ , p_φ )##. (b) The...

Assuming for now a simple photon particle model for light, where you have a stream of photons traveling with a certain frequency. Picturing this in my head on a number line, with just 3 photons at a time, and let's just say the wavelength is 1 and speed is 1, and at time t=0 we have a photon at...

I would like to prove that ##\displaystyle{\int dx'\ \frac{1}{\sqrt{AB}}\exp\bigg[i\frac{(x''-x')^{2}}{A}\bigg]\exp\bigg[i\frac{(x'-x)^{2}}{B}\bigg]=\frac{1}{\sqrt{A+B}}\exp\bigg[i\frac{(x''-x)^{2}}{A+B}\bigg]}## Is there an easy way to do this integration that does not involve squaring the...

Hi, I have a question that has been bugging me recently. It's about the berry phase and something that I find contradictory. One can see that it is possible to get rid of 2π x (integer) part of the Berry phase by means of a gauge transformation. This in general applies to phases (gauge...

Homework Statement Two parallel wires have currents passed through them which are in the same direction. Draw a diagram showing the directions of the currents and of the forces on the wires. Alternating currents are now passed through the wires. Explain what forces would act if the currents...

I know the units of Kc are mol/liter. The units of Kp are either mol/atm or just atm. Not really sure. I get mles atm and liters in my answer when i solve. Pretty weird

Homework Statement I'm given two frequencies: 4,000 Hz, and 5,000 Hz. They are completely in-shift at time ##t=0##. I am to find the time it takes them to get completely out of phase. Homework Equations The Attempt at a Solution I've not gotten waves very well thus far in physics. My teacher...

Homework Statement A 1x106 kg piece of ice is placed into a lake. How much heat is taken from the lake to raise the temperature of the ice from 0 °C to 1x10-20 °C? How much volume does the lake increase by? Latent heat for water is 334x103 J/kg Homework Equations Found in my textbook, cice =...

1. The problem FIGURE 4(a) shows the circuit of an oscillator and FIGURE 4(b) gives the gain and phase response of the op-amp used. When the circuit was simulated in PSpice using an ideal op-amp, the circuit oscillated at the designed frequency. However when the ideal opamp was replaced by the...

When solving the differential equations for an electromagnetic wave you get out that the electric and magnetic field oscillate in phase. But when considering a oscillating dipole, the electric and magnetic field at a point close to the dipole are a quater period out of phase. Can someone please...

Why won't water wave undergo a phase change of pi when it propagates to a fixed wall just like a pulse of string does.

Ice melting in a box has the water coming off it at a temp just above freezing until all the ice is gone. Are all phase change materials pretty much the same, with their immediate containment container exterior staying pretty much just above their phase change temp until all the PCM inside has...

I'm working on a project with a team in building a motor. My task is to find a controller for the motor, but I haven't had much luck. Here are the specs for it : Permanent magnet synchronous motor, 3 phase 8 pole 2 layer winding 100 kw power 400V The motor is AC. If somebody can even point me...

Homework Statement A lossless transmission line has an inductance of 9.0 nH / m and a capacitance of 3.6 pF / m. a) What is the line's characteristic impedance? b) Calculate the phase constant of a frequency of 1 GHz. Homework Equations Equation of characteristic impedance of a transmission...

Hi all, I have a difficulty to understand the concept of phase velocity of a wave packet. I read some materials online and my text, I didn't find a very straightforward explanation on this concept except the math definition. I also read some threads from this forum, but still have some...

In statistical physics, the partition function should be calculated in the whole phase space.This is finally an integral over the phase space, like ∫d3Nqd3Np... The problem is that the integral covers some cases that different particles have the same generalized coordinates and momenta. So, is...

Homework Statement A = 20 cm Given the graph, what is the phase constant(in degrees)? (I have already solved for amplitude and frequency) Homework Equations x(t) = A cos (wt + ϕ) The Attempt at a Solution x(t) = A cos (wt + ϕ) Taking from t = 0, we find: 10 = 20cos(w*0 + ϕ) 10 = 20cos(ϕ) 1/2...