Current Definition and 1000 Threads

Interested in Banks' HST these days, for discussion,here are some abstract and an email from L.Smolin. A recent conclusive paper as well https://arxiv.org/abs/2201.06988 The formalism of Holographic Space-time (HST) is a translation of the principles of Lorentzian geometry into the language...

Recently I've seen many fixed FR(or Wigner's friend) thought experiments.For example, https://arxiv.org/pdf/2011.12716.pdf is a zero-cited paper that presents a strenthened version of FR ,and claims to have solved its weaknesses.The author claims that it supports the idea that the "C"(for...

i have use time evolution operator to get the wavefunction at any time "t" as Ψ(x,t) = U(t,t1) * Ψ(x,t1) but i don't know how to calculate next part of the question

I know that if there is only one conductor providing the current density, then the current density can be used. But if you apply Maxwell's equation when there are multiple current sources, I don't know which value to use. This is not an analysis using a tool, but a problem when I develop the...

I am currently studying to solve Maxwell's equations using FEM. I have a question about Maxwell's equations while studying. I understood that the magnetic potential becomes ▽^2 Az = -mu_0 Jz when the current flows only in the z-axis. I also understood the effect of the current flowing in a...

how does capacitors and inductors cause phase difference between current and voltage? how does complex number come into play to explain the relation between phase of current and voltage?

Summary: Current using jω method with 3 components in the following series : Resistor, capacitor and Inductor. I have the following information: R=1 * 10^3 ohm L = 0.5 H C = 0.1 * 10^-6 F v(t) = 230 * sqrt(2) * sin(2pi * 400 * t) All the components are in parallel as shown in the image...

Hi. I want to ask a quick question, how accurate are multimeters? Like is every current detected on a multimeter a legitimate current or can it sometimes detect false currents, and can it miss any currents that are there? And how accurate are the values on there when it comes to what the current...

vcanoe_wrt_ground = 3 m/s + (-6) m/s = 3 m/s - 6 m/s = -3 m/s Thus, if I understand this correctly, the rower will never reach his goal 36 m away as his canoe's resultant velocity is negative (i.e., his canoe is effectively going downstream even though it is trying to go upstream). My only...

I want to understand if LED's which are used in the vehicles have Peak and nominal current? This is to know the hardware design to support the LEDs with peak currents, if both peak and nominal currents are same we can design a single board else the hardware design shall also consider the peak...

hello : i saw a sat book few days ago and noticed that it is only english and elementary math , i was surprised do you need to pass only sat to enroll in a university why there is no sat object , for example sat physics , sat math , sat chemistry ,...etc in order to help student with the sat...

The amplitude of ##\vec{B}## is given by: $$B(x) = B_{0} - B_{0} \frac{x}{2l}$$ for ##0 \leq 0 \leq 2l## This was my attempts at finding the flux of B: $$\Phi(B) = (B_{0} - B_{0} \frac{x}{2l})(2l-x(t))l = B_{0}2l^2-2B_{0}x(t)l+ B_{0}\frac{x(t)^2}{2}$$ and the current: $$ i = -\frac{d...

Hello everyone! I've been trying to solve this circuit but there's something wrong. Firstly, I made a Delta-Y conversion so that1 and zA were in series, and so were z5 and zb. I really don't know if writing "I0=IA-IB" is correct, cause basically I0 is the current that flows between the nodes A...

The fact that the current changes in time should allow me to take it outside from the integral along the coil, since it is not a function of space. But I'm not sure about this assumption, is there something I'm missing or am i correct? Thanks

I have two related but separated questions: 1. If I have an open circuit connected to a battery, let's say an alkaline battery connected to a straight wire and nothing more, once I connect the battery to this wire there will be for a short time a current in the wire? Since in the battery due to...

I'm sure this gets asked a lot. CPUs and GPUs still kind of mystify me, since I do not know their science. It came to me after studying some computational linguistics that it might be possible that in the next 100 years, we might have smart-translating, smart-talking machines without a theory...

I know how to calculate the standard Landau pole result at one loop suggesting that a quantum field theoretic treatment of the electromagnetic force in the continuum is trivial. I am wondering does this result continue to hold at higher loops, nonperturbatively or when electromagnetism is...

"M. Shupe [Phys. Lett. 86B, 87 (1979)] has proposed that all quarks and leptons are composed of two even more elementary constituents:" (Griffiths) I am redoing the book of elementary particles from Griffths, and this exercise has showed really interesting to me. How is the currently status of...

What are the current limitations with solar sails and why are they not used with greater frequency? I have heard of hydrogen blistering -- is that a significant issue?

https://www.cisco.com/c/dam/en_us/training-events/netacad/demos/CCNA3v3Demo/PDF/lab_1_1_4.pdf This is the pdf I am studying from. This is not exactly what I need for my exams but it’s pretty clearly written and concept giving thing. 192.168.10.0/24 is given IP address to subnet. We need 4...

In alternating current, is the resonance state that the phase angle of the current is 0?

Hello guys, LRC circuits with an AC source are having the best over me... had some confusion in class with respect to which method is best using(phasors diagram, reactances or complex impedances) which I am trying to desperately sort out before my exam; here I will show you my best attempt on...

Hello everyone, I'm working on a home project to create AC current, using magnets (AC Generator). I understand the principles of how to generate AC current however, I lack the complex knowledge of the physics side. I have searched and watched various Youtube videos etc, but none of them answer...

##I_2 = \frac{V}{R_3 + R_2}e^{-t/\tau}## ##I_2 = \frac{50}{19.4(2)}e^{-t/\tau}## as t goes to 0, ##I_2 = \frac{50}{19.4(2)}## = 1.29 Amps which is not the answer.

(An even longer-winded version was written and deleted out of mercy.) Assume an AC voltage at zero degrees applied to an ideal parallel RLC circuit. For a predominantly inductive circuit, the vector diagram for current should show the supply current in the fourth quadrant (i.e. with lagging...

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The second equation gives the magnetic field at a point away from the center of a circular current. If we multiply this by the the area we get a function for the magnetic flux. We have an increasing current which induces an increasing magnetic field. Now just solve for x in the second equation...

I set up the equation ##V-iR-L\frac{di}{dt}=0##, with ##i(0)## and by solving it I got ##i(t)=\frac{V}{R}(1-e^{-\frac{R}{L}t})##. Then, since the steady state current is ##i_s=\frac{V}{R}## I imposed the condition ##i(t_1)=\frac{9}{10}\frac{V}{R}\Leftrightarrow...

I have a chemistry project and my research question roughly translates to: What is the effect of the different metals electrolytic nature on iron corrosion? (In french: Quel est l’effet de la nature électrolytique de différents métaux (cuivre, aluminium, magnésium) sur la corrosion humide du...

Hello there, I am given a diagram of a Josephson Junction like so: With a magnetic field ##B = \mu_oH## in the z-direction. I'm reasonably sure ##d_x,d_y,d_z## are normal lengths, not infinitesimal lengths although that is up for debate. Using the above equations I rearrange the expression...

Hi everyone! I'm pretty new in this forum, I found the topics here very relevant to my physics course. And here is my question: Given the following drawing, two infinite sheets (in y and z axis) of ideal conductive material. their thickness is infinitesimal (dx->0). The electric field is...

I recently watched this video by David Tong on computer simulation of quantum fields on lattices, fermionic fields in particular. He said it was impossible to simulate a fermionic field on a lattice so that the action be local, Hermitian and translation-invariant unless extra fermions get...

Homework Statement:: This isn't a homework question but just a theoretical questions. [mentor’s note: moved to a more appropriate forum for theoretical questions.] I know that current is defined as the rate of change of charge per unit time. i = dq/dt This makes sense for a capacitor which...

How would you unify the two Lagrangians you see in electrodynamics? Namely the field Lagrangian: Lem = -1/4 Fμν Fμν - Aμ Jμ and the particle Lagrangian: Lp = -m/γ - q Aμ vμ The latter here gives you the Lorentz force equation. fμ = q Fμν vν It seems the terms - q Aμ vμ and - Aμ Jμ account for...

Hello , I was looking into current density analysis of a PCB that handles distribution of AC power . from ansys and cadence sites , i realized by current density they refer to DC IR drop that is a pure ohmic analysis that doesn't take into consideration the AC effects . And in order to take this...

Hi! I'm trying to understand electromagnetism. So I had a question: if we place a bar magnets on the low friction surface near vertical wire, then switch on the current, what will happen? As I been told they will align with the magnetic lines, and then nothing will happen. I also suggest that...

I shorted the inductor and performed mesh analysis. The solutions to the linear system were done using a calculator. The book says that the value for i2(0-) should be 15 mA but I'm getting -2mA. What am I doing wrong? I'm completely confused. Maybe mesh isn't the most efficient way to find I2...

Yeah so I'm confused about this circuit because it has an overlapping path. My guess is that the current doesn't flow in one of the two paths in the middle but I don't have a good reason for it (I don't know why). I suppose there is symmetry but I haven't been able to find good videos on...

Voltage SI unit = Volts Current SI unit = Ampere Resistance SI unit = Ohm Ohm's law : V=IR Did Georg Ohm (German), Ampere (French) & Volta (Italian) collaborated when Ohm came out with this electricity equation with units for voltage, current & resistance as per their surnames? Credit goes to...

I have to prove three equations above. For first two equations, I've been thought and made reasonable answer by using a definition of the electricfield. However, for third, I can't use a definition of a magnetic field due to the cross product Like J_2 X J_1 X (r_2 - r_1). I think three of 'em...

So basically we can have a constant current but i don't understand this circuit. for example: i can have the Ia what ever I want with current divider rule: Ia = Iq * R2/R3. So Ia is proportional to the ratio of R2/R3. And if i give a resistor at the collector terminal, if i change it between...

I honestly have such a dumb question- it says “a pitch angle” but cannot find that in relation to a helix. It is not defined in the textbook. Looking on google I found a helix angle, but is that different than the pitch angle? Can anyone draw me a picture of where the pitch angle is? I assumed...

Is it because the current applied to a capacitor will never be time independent? Please help me out🙏

I am not an educated man, so please try to answer in Layman's terms. It makes no sense to me. How and Electrical circuit that has X amount of current flowing through it, and X amount of current being used by a Device. I.e. a Washing Machine, Light bulb etc. have the same current flowing out of...

My wife read an article last night about an outbreak of hemorrhagic fever in rabbits, and it has been passing through populations throughout the US. So, I decided to look into it and came across a wildlifehealth.org. There is a lot of nasty stuff out there. Detection of High Pathogenic Avian...

I did a kvl loop and got V + 5Io - 15 Io = 0 So, V = 10Io Then, substituted dq/dt for Io and q/c for V I get to dq/dt - 50000q = 0 solving this equation i get q = C x e^50000q (c for constant) my Io = dq/dt so Io now is 50,000Ce^50000q now my Q(0) is 3 x 10^-5 So my Io (0) should be...

Hi, I have the following question from an old City & Guilds paper: A resistive load rated at 65 W, 110 V is to be used on a 230 V, 50 Hz supply. Calculate (a) current in the load (b) voltage drop needed across a pure inductor connected in series with the load (c) inductance of this...

Hi, I need to calculate the temperature of a wire, due electric current passing through, and I have no idea how to do that. I need it for a device that I want assemble. I'm using one single thread (strand) of speaker cable, like you can see in this picture: Again, Just a single thread that...

Many years I read a lay person friendly article on Horava Lifshitz gravity. https://www.scientificamerican.com/article/splitting-time-from-space-evidence/ Im curious to know how has this theory developed? Is it taken seriously? What are the outstanding problems ? Have there been any impressive...

If I want to carry 10 A through an 8 AWG wire, I understand that there will be a specific magnetic field around the wire which will decrease as I move outward from the wire radially. Let's consider the center of that wire as coordinates (x,y)=(0,0). An object located at (0,10) would see a...