Phase Definition and 1000 Threads

If i am given the de broglie wavelength Of any particle then its sure that i can find the velocity of tat particle if its mass is given. λ= h/mv But the velocity which i found is the group velocity or phase velocity?If it's not the group velocity How can i find it?

Find the function with the given derivative whose graph passes through point P. $$r'\left(\theta\right) =6+\sec^2 \left({\theta}\right), P\left(\frac{\pi}{4},0\right)$$ 6+sec^2(x) The phase shift appears to be 1 but not sure how to get that How do add another equation to desmos?

Good morning everyone! My chemistry final is approaching and I have a few difficulties in the thermodynamics chapter. One of the things that are bothering me is the calculation of the temperature of phase change. We know that if a mole of ice at 273K melts, the entropy change would be...

Single phase motor is not self starting, so it is started using some arrangement and the starting arrangement is disconnected(not always) once the motor is set in proper motion(about 70% of the maximum speed). But I didn't understand this graph. From the starting moment, motor accelerates and...

Homework Statement So, my teacher said that the biggest phase difference is pi. But what if you have two waves arriving at a point, such that the instruction from one wave is a phase of (7pi/4), and from the other is (3pi/4), then the phase difference is (9pi/8), which is larger than pi. So...

Homework Statement X'=x-y^2 Y'=x^2 -xy -2xHomework Equations Find the critical point of this system. The Attempt at a Solution I know one point is (0,0). When I tried it I got sqrt(x)= 2 and sqrt(x)= 1 but the point (1,1) doesn't fit later parts of the question. I'm also aware that since a...

phase diagrams show the change of the state when temperature or pressure are modified. to achieve this, is necessary heat, but my questions is: would plasma state be described in this diagrams? is this figure true? because plasma state can be generated by heating.

Hi, So when you over-excite the rotor of a synchronous motor, or under-excite the rotor of a synchronous generator, how is the flux actually changing the power factor of the armature to leading? (something to do with the magnitude of the armature reaction flux vector?) That is to ask: by what...

I know there is a pi phase shift when going from an area of lower index of refraction to higher. Is this phase shift still pi when going from a non-conducting dielectric with index of refraction n and reflection off a "good" conductor?

According to Daniel Gillespie in A Quantum Mechanics Primer (1970), " . . . any observable which in classical mechanics is some well behaved function of position and momentum, f(x,p), is represented in quantum mechanics by the operator f ( \hat{x} , \hat {p} ) . That is, a = f (x,p) . . ...

Hello everyone. I have been practicing for my exam in fiber optics, and stumbled upon the following question: We have a transmission system with 3 channels, composed of a single mode fiber and a dispersion compensation fiber. Specifications are given for each. We need to calculate the channel's...

Homework Statement how to visualize group velocity and phase velocity? I tried to to visualize it The velocity of up and down vibration Of the wave as phase velocity. And The velocity of the whole wave in propagating direction as group velocity. AM I CORRECT OR WRONG? Homework EquationsThe...

They say 3 phase system requires less conductor then single phase why that is so if we consider diagram below? Also why here current going out when neutral is there in form of earthing

Homework Statement Three loads ZA = 10∠0° Ω; ZB = 15∠-30° Ω and ZC = 20∠45° Ω are connected in star across a balanced, 3 phase, 400 V, RYB supply. Determine (a) line currents (b) Phase Voltages (c) Neutral shift voltage, VON Homework EquationsThe Attempt at a Solution My query is that in...

I am trying to convert a 240/120V 60Hz genset for international use, specifically for China at the moment. I need 50 Hz, which I can achieve by slowing the engine down and making the necessary changes to the voltage regulator in the generator. I can also adjust my Line-to-Line voltage to the...

Hello I am confused and I can't figure out what is meant by phase when it comes to quantum mechanics for single photons and coherent states as I am a new to this field. Best regards

Hi all, Having difficulty understanding the above resultant wave form, been looking at power electronics (C.W.Lander) but don't quite get the addition of the wave forms (positive and negative cycles)can anyone point me to some reading of theory I am missing for this, thanks.

I believe I can explain why there is energy needed to break intermoleculares bonds and getting into a gas or liquid, but the other way around confuses me. Bonds have potential energy associated to it, so It's needed work to break the bonds, because we would be trying to move a molecule away from...

Homework Statement [/B] Hi there! This is a question from a practice problem sheet I got from the lecturer of my Condensed Matter 1 course. Below are the normal vectors to the {111} and {112} lattice planes: Homework Equations [/B] Bragg Condition: \begin{equation} n \lambda = d \sin...

I have troubles for designing a 3 phase inverter, and I cannot find the formula everywhere...

Hello folks, Can someone explain me the source current reversal in single phase rectifier having source impedance. I understood the analysis and functionality, but having a hard time understanding the change in current in source impedance from +ve to -ve. How load voltage is zero at this...

These days, I designed a Bragg grating using FDTD Solution. But when I try to get its phase information of the transmission spectrum, I meet some trouble. Could anyone give me some suggestion? Which monitor should I choose? Or should I use INTERCONNECTION? Thank you !

In an earlier thread of mine, another physics forums member was nice enough to point out that there is an uncertainty relation between photon number and wave phase for light. https://www.physicsforums.com/threads/is-there-a-frequency-eigenstate-for-light.727141/ Now I am wondering, where does...

Homework Statement Acording to the Gibbs phase rule, what is the maximum number of phases that one may observe for a binary mixture in equilibrium? Homework Equations phase rule F=C-P+2 The Attempt at a Solution It says binary mixture but does it mean there are 2 component(C=2)? I think...

Hi everyone I'm taking a linear algebra class at university right now and this is one of my homework questions . I am unsure how to even approach these questions. Any pointers in the right direction would be greatly appreciated. I apologize in advance for not showing any attempt at this...

Hello, Am having this confusion that in Boltzmann approach to Statistical Mechanics, the phase space was divided into small phase cells whose magnitude was of the order of (h^f) but Boltzmann also made the assumption that the smallest phase cell must contain a large number of atoms. Doesn't this...

I have a few questions about AM, FM and PM. 1. If FM (or PM) radio modifies the frequency of the signal, how is the signal picked up without having to change the frequency constantly? 2. If PM modulates phase, which modulates frequency, what is the difference between PM and FM? 3. Why is AM...

Why mesons mixed states are defined as SOMETHING +/- SOMETHING [+/- SOMETHING] normalized by 1/sqrt(2) or 1/sqrt(3), So the sum uses quotient +1 or -1. But in electroweak symmetry breaking charged W boson is defined as W1 (+/-) i*W2, so the quotient is +i or -i. So why mesons never use...

In what phase of matter do individual Neutrons/Protons/Electrons exist? They are matter aren't they? So they must exist in some phase, right? Do they change phase? I'm very curious any information would be greatly appreciated. Thanks!

Urs Schreiber submitted a new PF Insights post Higher Prequantum Geometry IV: The Covariant Phase Space - Transgressively Continue reading the Original PF Insights Post.

I am looking to build my own rotary phase converter for utilizing 3ph devices however I am having a difficult time wrapping my head around the aspect of producing 120* out of 180* power. PracticalMachinist forums have a plethora of threads on this topic but after reading many of them I find...

The wikipedia article mentions that the model allows for "phase transitions" but doesn't specify what it means by this? What is a phase transition in the context of an ising spin glass? Is it when the mathematical model of a magnet, changes from solid to liquid? In this paper...

Homework Statement [/B] What is the maximum full-load primary current that you could safely design for a three phase 500 kVA transformer bank to provide if it has a high-voltage winding of 25GndY/14.4 kV? What does the notation 25GNDY/14.4kV really mean? Is it 25kV three phase and 14.4kV...

Hey! I am currently working on modeling and solving a scenario with oil and water flow. The flow is supposed to be driven purely by the capillary pressure(Dont mind this too much). The flow in the two phases are given by: q_o = -\frac{k_o(\Delta P)}{\mu_o}\frac{\partial P_o}{\partial x} q_w =...

Simple question, What's the advantage of having more phases in an inverter? Like why have 6 or twelve phases? Is it something to do with harmonics? I know that the higher the switching frequency the further off in the freequency spectrum you can push the harmonics, but I can't see that being...

If you're using a phase contrast microscope and the refractive index of the medium is equal to the refractive index of the cell, what are you able to see? I guessed that you wouldn't see anything, but apparently that's wrong. The only options are membranes, vesicles, the nucleus, pigment...

So I'm really rusty on phasors, I was reading that a space vector current was i(t) = I(cos(wt)<0 + cos(wt - 120)<120 + cos(wt - 240)<240 ) = 3/2 * I < wt and I couldn't figure out how that could be so (still can't, please help) So I tried to go back to basics and I went back and read: A =...

There is a liquid phase homogeneous reaction going on in an CSTR, which operates at 4 atm. Is it necessary to have pressure relief valve? If so, what will be vent out when the pressure exceeds, since it contains liquid only?

Hi, I'm confused about the discussion on p28 of Nigel Goldenfeld's "Lectures on phase transitions and the renormalization group" (this question can only be answered by people who have access to the book.) The goal is to compute the potential energy of a uniformly charged sphere where the...

Homework Statement Suppose a room with 75 m3 of air also contains 80 kg of glycerol and the initial temperature in the morning is 16 °C. If 1.2 kWh of heat is added to the room between morning and afternoon, calculate the final temperature of the air in the room in the afternoon. Use 18 °C for...

We know that the universe is expanding at an accelerating rate. In big bounce (or oscillatory) models of the universe, why does the expansion of the universe end? And what drives the following, contracting phase? Is it possible that dark energy could inverse its action at some point in the...

Homework Statement Suppose a room with 75 m3 of air also contains 80 kg of glycerol and the initial temperature in the morning is 16 °C. If 1.2 kWh of heat is added to the room between morning and afternoon, calculate the final temperature of the air in the room in the afternoon. Use 18 °C for...

Homework Statement I took a few pictures of the circuit, it went across two pages so I took a few pictures, and closeups of certain parts to ensure that all the details can be seen For the circuit: http://s7.postimg.org/ywd4nrmsq/IMG_20150905_140403187_HDR.jpg Figure 1. Overview of Circuit...

Homework Statement SOURCE: v(t) = (311)cos(314t) [v] IN SERIES WITH: R = (0.3) [Ω] L = j(0.7) [Ω] "load" = 2.5 + j(1.0) [Ω]Homework Equations Find the instantaneous current, and the phasor current. The Attempt at a Solution (1.) I first found the frequency of the source: (314) / (2*pi) ≈ 50...

Hi All, I've heard it said that the superluminal phase velocity of the KG eqn is not a problem for relativistic causality because signals travel at the packet/group velocity, which is the inverse of the phase velocity (c being 1). I'm a bit skeptical of this. We can strip away all the quantum...

I am curious as to the meaning of, and name given to the phase ##\xi(t)## which may be added as a prefix to the time evolution operator ##\hat{U}(t)##. This phase acts to shift the energy of the dynamical phase ##<{\psi(t)}|\hat{H}(t)|\psi(t)>##, since it appears in the Hamiltonian along the...

Homework Statement Good Day, On an oscilloscope, when two incoming signals are out of phase, in an XY setting, an ellipse appears on the oscilloscope screen. The phase shift between the two incoming signals can be found by the formula: sin^{-1}((Y_{max})/(Y_{int})) where Y max is the...

Q6c) Why is the phase difference between two points in a stationary wave equals to zero? I understand that a stationary wave is formed by two progressive waves which have the same amplitude, frequency, wavelength and speed, but traveling in opposite directions.

Is the phase space of the universe, including it's partitioning, defined and calculated from the the SM?

Hi, I'm wondering if people could help me compile a list of ELECTRONIC phase transitions, that are FIRST-ORDER, that occur at room temperature and can be driven by things like doping, strain, magnetic fields, etc. rather than temperature. Any suggestions are greatly appreciated. Also, would...