Phase Definition and 1000 Threads

Homework Statement This is a statement i found in one of my textbook of "Antenna analysis". The phase front of a exponential time varying quantity(charge distribution) 'ejwt' is a spherical wave front and is represented by e-jkR. Homework Equations 1. How can we represent spherical wavefront...

Homework Statement There is a spring with 2 masses with a combined mass of 0.69kg. The vertical oscillation has a frequency of 1.5Hz. The amplitude of the oscillation is 30mm. Now this spring is attached to a horizontal support rod that can be made to oscillate vertically. how do i work out...

I have created a circuit diagram for a single phase CSCR induction motor, but only for the purpose of calculating start-up current (i.e. motor speed is at, or very near, zero RPM). I have created this diagram because: 1) I do not have the tools & knowledge required to generate the Steinmetz...

Homework Statement When completing this problem I am able to find a value for the phase angle but am unsure of how to find the quadrant for the phase angle therefore unable to get the correct phase angle. Homework Equations Provided in the question: x = xmcos(wt+ phi) The Attempt at a...

So assuming I1 = 1<10 and I2 = 2<20 And assume these current sources are in parallel, pointing in same direction. Can I say total current is I1 + I2 = 1<10 + 2<20 ? I would convert the phasor to complex number to combine them, but will this work?

Homework Statement I need to calculate the power for phase A, B, and C so that I can determine the total power into the system. I have measured the following data: VA magnitude = 117.7 [v] VA angle = 0° IA magnitude = 7.5 [A] IA angle = -25.5° VB magnitude = 117.7 [v] VB angle = -124.1° IB...

Homework Statement Consider a gas (note: treat as ideal) that has phase coexistence between diatomic and monatomic forms at ##T_0## and ##P_0##. Compute the equation for the P,T phase boundary between monatomic and diatomic gases. Homework Equations ## u_v (V,T) = \frac{5}{2} RT -...

I just read some words from the book Optical Waveguide Theory by Snyder, Allan W., p226. It says that "However, although it is possible for the phase velocity of a mode to exceed the maximum speed of light in the cladding (of waveguide), c/n_cl, this cannot occur without losing power to...

Classically, we explain why light appears to move slower in glass by saying that the electrons in glass emit a light wave which is 90° out of phase with the light wave shaking them. However, the electrons would have to emit this wave not only in the incident direction, but in the opposite...

Homework Statement I studied that as the single phase motor speeds up the backward induced field currents are larger than the forward field currents. So , the corresponding opposing rotor mmf causes backward field to be greatly reduced whereas the smaller forward currents leads to enhancement...

Are the E and M components of an E-M wave (at a given frequency) necessarily in phase in free space? A conductor? A dielectric material?

If you produced a focused beam from, say, a cassegrain transmitter which consisted of two waves merged but one inverted what would be the result. I presume there would be destructive interference. My question is, where does the energy go?

Hi. My colleagues and I are doing a research on transformers (single-phase) and we stumbled across the following equations involving hysteresis and eddy current losses: Wh = ηBmaxxfV where Wh = hysteresis losses η = Steinmetz hysteresis constant Bmax = maximum flux density x = constant...

Homework Statement Given two waves characterized by y1(t) = 3 cos wt; y2(t) = 3 sin(wt + 60deg); does y2(t) lead or lag y1(t) and by what phase angle? Homework Equations y1(t) = 3 cos wt; y2(t) = 3 sin(wt + 60deg) The formula I'm given in my book Fundamentals of Applied Electromagnetics is...

Why can't we have an Electromagnetic wave in which the Electric Field and Magentic Field aren't in phase?

First post ! I hope that my question will not make some long time physicists laugh. It is about geometrical quantization and the phase space in which we use : z=1/sqrt(2)(q+ip) My question is simple what is this 1/sqrt(2) ? And what is it is interpretation ? Thank you !

My lecturer said the following: (see uploaded image) However the two statements are not the same, which is correct? thanks

Dimension of Phase Space of a rigid diatomic molecule is 10. Shouldn't it be 12?

As I'm seeing things, there are these choices for a definition of relativistic phase velocity u; a) u = (mc^2)/ p b) u = E / p Now I like choice a) because it leads to a correct-looking index of refraction via n = c / u. It leads to a correct-looking solution to the ray equation. However...

I have been told that phase transitions=physical equilibriums. How can phase transitions be physical equilibriums? For example, if you have liquid water going into gas phase, doesn't delta G have to be greater than 0 for the phase change to occur? Is physical equilibrium an assumption in phase...

Hello there, this is a fact that I can't understand thinking about it... Energy has to be given so that the inter molecular bonds can be broken, and energy goes in when there are formed (even though that sounds very counter intuitive to me), but why is the energy all distributed to potential...

I am planning to run 230V single phase machine with 460V single phase supply. what will be the effects in RPM and torque? (( this is how i thought: as we increase voltage , current will decrease since power is same...decrease in current decreases the torque...to maintain same power, decrease in...

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...