Phase Definition and 1000 Threads

Velocity of phase wave in vacuum is grater than light velocty. This contradict the princles of relativity,so how this can be possible.

Hi! Is it possible to measure phase angle in Multisim? I want to measure phase angle of current through capacitor C1: I got by hand ic1(t)=0.117*sqrt(2)*sin(2*pi*50*t-178.040deg) Thanks in advance.

In the recent analysis by Mielczarek, Linsefors, and Barrau, the key parameter is ρc the highest density achieved in the bounce. The extremes (negative and then positive) of the Hubble rate occur symmetrically at density ρc/2 In the contraction preceding bounce, as the density approaches ρc/2...

I have an online homework question and my classmate told me the answer but I would really like someone to explain to me how that answer was determined. I do not understand. Q: Consider the electric field observed at a point O that is far from the two slits, say at a distance r from the midpoint...

Hi, if I simulate a three phase transmission line operating with a fault across two of the phases, would the mutual coupling have any effect on the current through each of the lines, as I have calculated the fault current values using symmetrical component analysis and the values are...

Hi Im doing a project to control a 3 phase switch relactance motor using power electronics. I have choosen 3 mosfets, 2 auto couplers and 2 resistors. 1. Would there be any other devices I need ( to solder to pcb board). 2. What would the circuit digaram look like so I can solder this and...

Hi PF I read the definition of the displacement operator: ##D(\lambda) = e^{\lambda a^\dagger - \lambda ^* a}## but i did not find how this operator can be implemented say in a cavity with a photonic state inside. Could you give me links? thanks.

< Mentor Note -- thread moved from EE to the Homework Help forums >[/color] I'm studying for a Level 3 Diploma in Electro technical science. My tutor had a hard time teaching me what I need to know in order to answer this question; Calculate the phase and line current when three resistors each...

Hello all I know that the step response of a second order underdamped system is : y(t) = 1 – (e^(-ζωn*t) / sin(θ))*sin(ωd*t + θ) Where sin(θ)= sqrt(1-ζ^2) , ωd = sqrt(ωn^2 – ωn^2 * ζ^2 ) my question is: I can see on the simulation ωd and I can calculate it , but I want also to see the...

Homework Statement Hi, This is not a homework question. I have my exam for my physics unit tomorrow. I am pretty set for it except for questions of this type. Can you please show me how I can get the answer? Thanks [/B] Homework Equations N/A The Attempt at a Solution N/A

Hi everyone, is it possible to sum at any given moment in time L1 + L2 + L3, algebrically speaking? If so, what would this value represent? Thanks

Homework Statement An aluminum cup (of negligible mass) is filled with 0.5 kg of water with a temperature of 15◦C and 1.3 kg of ice (at -8 celsius) is added. A)What is the final phase or phases of the mixture? B)What is the final temperature of the mixture? C)How much heat is required to raise...

What is the degrees of freedom at the critical point of a 1 component system such as water. in my test I put zero because the critical point is a POINT that is fixed per substance. is there any books that can back me up? I heard that my teacher said there was 1 degree of freedom which I am...

So a standing wave is one which looks to be standing still at certain harmonic frequencies. At these frequencies, when the wave reflects off the end, it will undergo a phase change of 180 degrees. This creates constructive interference as shown below: In the case of a wave on a string, since...

Hello! This is problem is a part of a bigger problem which I solved and came to a formula which is correct. This is the equation for one transfer function. The next thing I would like to find out here is when arg(H(jw)) is -90 or 90 degrees but I get stuck. Transfer function: ## H(jw) =...

Many websites gives the results of Dew Point but not the reason. What is going on at the dew point? Not the result (at a certain VSP vapour becomes liquid if it can find nuclei to coat) but the reason for the result. I have been reading up on this – just out of curiosity – and would like...

Hello Why are neutrino oscillations insensitive to Majorana phases? I'm guessing it has something to do with them being factored out the PMNS matrix using a diagonal matrix ... i.e. U_PMNS = U Diag (a1, a2, 1) Is there a point in the oscillation calculation where they always cancel due to a...

1. Is nucleation a phenomenon that occurs in all phase change (freezing/melting, evaporation/condensation)? 2. I've always read evaporation/condensation described as a liquid-vapour interface phenomenon (water molecules going entering-leaving the interface at equal rates in equilibrium). If...

Hi have some thermal physics question would like to clarify. Thanks :) Question 1: For a substance in a pure phase heated at constant pressure, the heat absorbed is related to ____________ (a)the molar heat capacity of the substance (b)the amount of substance (c)the change in the kinetic energy...

Hello again, I've got another question that involves symmetrical components, this time I've attempted it. The Question follows: 1. In a 3 phase circuit with resistance earthed and neutral and Earth fault in phase “A” which produces a fault current of 800 amps. Load currents may be taken as...

What exactly are the phases of orbitals/wavefunctions, for example the 2px orbital in hydrogen, what does it mean for the two lobes to be in different phases ?

Hello fellow engineers! I am a student doing a simple course in Electrical Engineering. I've got an enquiry regarding this question " 1. In a three phase 4 wire system with phase to neutral voltage of 230V, a balanced set of resistive loads of 8 ohms are connected between each phase and...

Homework Statement hi guys this is my first post, and it relates to classical mechanics. the problems asks that if there is a planet, planet x, with the same mass as that of the Earth and orbiting the same orbit as that of the Earth but 180 degres off from earth, so that the if the Earth is at...

Hi! 1. Homework Statement My task is to calculate amplitude and phase spectrum of this signal: Homework Equations My idea is to calculate complex Fourier series of this signal, $$f(t)=\sum_{n=-\infty}^{n=+\infty}Fne^{j\frac{2n\pi t}{T}},$$ where...

Dear Experts, When an electromagnetic wave moves from a rarer to a denser medium or gets reflected by a mirror, it encounters a phase shift of pi or (lambda/2), in that case, the reflected wave will be out of phase with the incident wave. I have a very basic (maybe non intuitive or even...

Homework Statement I have read that the phase difference between two sinusoidal signals is calculated as follows: $$\theta = \omega \Delta T = \frac{2 \pi}{T} \Delta T$$ Where ##\Delta T## is the time difference. This formula confuses me as it was derived from nowhere. I am asked to compute...

I am looking for phase diagrams for Mag-Thor alloys and would also like to get some information on how they are typically processed. Are these alloys typically made by diffusion of Th in the Mg and then thermally homogenized? Or are they usually cast? Perhaps made by some other process all...

Phase difference between two component of Electric field vector seems to me that the phase difference for circular should be of odd multiples of 90 but its not 90 when n value substituted. Please help for solution..

Hello I’m wondering if my understanding of how different processes relate to the phase diagram here is correct. 1) If a piston cylinder assembly maintains a constant 1atm pressure on some water and the water is cooled, we would be going horizontally along the red line from 373.15K to 273.15K...

Homework Statement f = 60 Hz pf = 0.8 (lagging) Homework Equations Z(L) = 2 (pi) * f * L Given z = x + iy tan(angle) = y/x pf = cos(angle) The Attempt at a Solution I changed the Wye-connected resistors to an equivalent Delta-connected resistors: The new resistors become 3R in the...

In several books I have seen the statement that due to Heisenbergs principle no particle can be localized into a region of phase space smaller than ##(2 \pi \hbar)^3##. However, Heisenbergs uncertainty principle states that ##dx dp \geq \hbar/2## -- so a direct translation of this should imply...

Hi all, I am trying to develop a motor protection scheme for the following scenario. There are two 3.3kV 250kW delta connected motors close coupled to a gearbox driving a crusher. Both have separate DOL starters and protection systems. What happens to the motor current in a motor that loses a...

please suggest me simple and pecise notes or book for the above that can provide full concept in a very short span of time perhaps this is not the homework.

Homework Statement a 4 kva, 230/115 volt, 400 HZ, single phase transformer originally designed for use in air crafts, is available in a laboratory for obtaining 115 volt supply from standard 230 volt,50 HZ mains if overloading of the device is not permitted then net kva output is...Homework...

Homework Statement https://www.physicsforums.com/attachments/question-jpg.73386/ the current go from a A N and n the 2nd current go from b B N and n the first thing, i make the matrix 27-4j -3 i1 230 <0 -3 27-4j x i2 = 230<0 x means the matrix multiplied to the next < means the degree then...

Hi there, I want to know what is the best way to connect these devices to a 3 phase power supply outlet and minimise the unbalanced load as much as possible safely? I am only worried about the single phase appliances. What type of connection would you recommend? 3x Power Supply units Single...

Wieland gave his ILQGS talk yesterday, 16 September. Audio and slides are on line. Title: Covariant loop quantum gravity: Its classical action, phase space and gauge symmetries http://relativity.phys.lsu.edu/ilqgs/wieland091614.pdf http://relativity.phys.lsu.edu/ilqgs/wieland091614.wav The...

Hello Guys, I got a Taifu QB70 water pump. But no more in use, I wish to use this motor in a gate opener project of mine. However I cannot figure out how to make the motor rotate in a reverse direction. What I tried ? 1. I reversed the position of the capacitor thinking it would...

Homework Statement i read some online notes. from there , i know that if the beat frequnecy ( difference in frequncies between 2 waves ) is low , then the time taken for two waves to be in phase again is very long... which means more number of waves has to be produced for two waves to be in...

In quantum mechanics, the phase of the wavefunction for a physical system is unobservable. Therefore, both ψ = ψ(x) and ψ' = ψ(x)eiθ are valid wavefunctions. For ψ = ψ(x), we have the following: \widehat{x}ψ = xψ \widehat{p}ψ = λψ For ψ' = ψ(x)eiθ, we have the following...

Hi there. I've been looking around for a decent physical explanation of the differences in the phase relationships between acoustic pressure and particle velocity in different types of waves. Mathematical analyses abound, e.g...

Homework Statement See attachment q2 for the perovskite structure The Attempt at a Solution For the perovskite structure, I assume that the lattice constant is equal to 2*(R1+R2+R3) and calculate the density based on this. Am I correct? (The attachment q2ans is my attempt on the...

Hi, I'm a medical student who is using ultrasound to measure cardiac strain. I'm trying to read up a bit on the physics behind doppler imaging (I did AP physics in high school), and I have a question for some genius out there. I keep reading that in pulsed wave doppler measurements, one does...

Phase difference between clocks with distance Homework Statement Derive Phase difference between clocks with distance Homework Equations I honestly don't understand how this equation ΔT = vD/c2 is derived/figured out. The Attempt at a Solution We haven't covered Lorentz...

Hey guys can someone please give me a good explanation on why in an RC circuit the resistor voltage is leading the capacitor voltage by 90°. While in an LC circuit the resistor voltage is lagging the inductor voltage by 90°. Thanks

I am learning about transformers and from everything I've read I can see how its possible to create a 180 degree phase shift by winding the primary and the secondary in opposite directions. What I wanted to know was if it's possible to make a 90 degree phase shift with a transformer.

http://forums.mikeholt.com/showthread.php?t=162981 I thought this would be a link worth sharing here on pf. We seem to have heated arguments going on this forum from time to time about which country has the best electrical system. There are some interesting things to read in the above link...

Consider a plane beam of light is falling normally on a material with thickness (d) and refractive index (n), the light partially transmits and partially reflects the light, so the light transmitting the light travels a distance (2nd) coming out of the material have a phase change of ∏ always...

Well! the material to be freeze-dried is irradiated with IR radiations before, why?? Also I am confused as to how can ice sublime at atmospheric pressure?? Isn't the triple point of water much lower? is the vacuum around the material created for this reason? ( to lower the pressure I mean) Also...

Homework Statement A radio station transmits a radio wave of 100Mhz. The radio wave is detected by a receiver via two diffrent paths , a direct path and refelcted path form a wall. The distance traveled by the radio wave for a direct path and refelcted path is 1500m and 1512 m respectively...