Phase Definition and 1000 Threads

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...

We have the KG Lagrangian density: \mathcal{L}= \partial_{\mu} \phi \partial^{\mu} \phi^* - m^2 \phi \phi^* Suppose instead of taking \phi \rightarrow e^{ia}\phi with a \in \mathbb{R} we take a \in \mathbb{C}. Then is it true to say that \mathcal{L}'= e^{-2~ Im(a)} \mathcal{L} and so gives...

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...

Folks, It's been a while since I've done calculations like this so I was wondering if someone can help me calculate the volume of a gas at a specific temperature as compared to its liquid volume when measured below its boiling point. I can't seem to find a phase diagram for this material, is...

Hi there. So here goes. I have been having issues with a replacement chiller unit that requires 230VAC single phase. An identical unit was running on 2 phases of a 110VAC 3 phase supply. I had a start capactior fail in this unit. When I connected the replacement unit, the compressor...

Hi! Ok, I got another question here. I don't understand how to draw the vectors. This is a method to simplify analysis of unbalanced three-phase power systems but I just don't understand the drawing here. Do you think you can explain how? I understand how to draw the vectors for Ia, but not for...

Take a look at the attachment, my question is obvious from the colored points. The attachment is from: "state-of-the-art formulas for helicity amplitude calculation and all that (version 2.4) PART Ia. Spherical-Vector Method for Helicity Amplitudes (FORMALISM) Ken-ichi Hikasa" I think...

Hello everyone,can anyone help me to understand the phase congruency principle. I have read that,in image processing if we reconstruct an image using its phase only,we can get obtain edges and lines and this is because of phase congruency principle. I am searching more about phase...

What is phase velocity? I know it is defined as v=ω/κ But what does this phase velocity tells about the wave? Does it means the velocity of wave?

Hello, I know that the latent heat of a first-order isothermal and isobaric phase transition is in general given by the difference in enthalpies between the two phases, but my question is: do you know if there is there a way to estimate its value "from first principles" for the case of a...

I'm having difficulties understanding the role of scattering on phase coherence in the Aharonov Bohm Effect. In particular I am trying to reconcile the following points: Inelastic scattering destroys phase coherence and prevents us to see the Aharonov Bohm Effect. Elastic scattering does...

I want to design a single phase induction motor (1/3 HP,50Hz,220V). I face a problem to design the main dimension of stator and Slot shape and Rotor skew angle . Would you give some idea for design ? or any related book and software ?

https://www.physicsforums.com/showthread.php?p=2881300#post2881300 According to the quoted thread above and according to textbooks and Wikipedia the phase between the E and B fields of an electromagnetic wave propagating in free space is zero. This assertion is based on the Maxwell equations...

I am a Grade 11 student and am working on a physics research about Fraunhofer diffraction. I have 2 very basic questions (maybe kind of unprofessional). Hope someone can help. 1.Suppose a beam of coherent, monochromatic, parallel light penetrates an object, and a diffraction pattern forms on...

Hi All, I have access to a 15kW VFD for little money. I only have single phase 240 vac at home, and need to drive a 10kW motor, 3 phase, 415v. I have been reading that 3 phase input VFDs can be run on single phase, but they must be derated by 50%. This would mean a 20 kW VFD. Also, it is a...

Hi, I'm really stuck on this assignment question and could do with a hand on the step by step process of how to get the answers. A three phase induction motor as 2 poles, a standstill voltage of 121 v/phase (Er), rotor resistance of 0.15Ω/phase (Rr) and a standstill rotor reactance of...

Homework Statement I have an exam coming up and one of the practice questions is as follows A 415V 50Hz three phase supply energises a balanced star-connected load through a three phase feeder with a per-phase series impedance of Zline = ( 0.165 + j0.413 ). A power meter at the source end of...

For a school project I need to be able to shift the phase of a 100 kHz sine wave by 90 degrees (either positive or negative). I have tried several passive integrators and differentiators, both with poor results. I have also tried using an op-amp integrator and differentiator, but in both cases...

Hi I have been trying to find the types of equipment required to protect 3 phase generators+transformers for a while now but I just cannot seem to find anything. If you could help me out and give me examples of the equipment it would be greatly appreciated Thanks

Homework Statement the turntable is rotating at 36.25 rpm. the simple pendulum is performing SHM at 36.00 prm. how many complete oscillations would the pendulum execute so that both are in phase? Homework Equations The Attempt at a Solution my working is 36prm divided by 0.25 rpm...

Homework Statement the question doesn't state that which particle is leading/lagging which particle. Homework Equations The Attempt at a Solution for the first particle, my working is 10 sin(2pi/3 )= 8.66cm for the second paticle, my working is 10 sin(2pi/3+ 30pi/180)= 5 cm...

How to prove that energy travels at group velocity and not phase velocity?