Current Definition and 1000 Threads

Good evening to everyone! I'm pretty new in this kind of job, so every help or advice will be helpfull and I will appreciate it. I know that short circuit current from picture in attachment depends on impedance and reactance of Source MV, transformer example (10kV/0.4kV) and cables. So if I...

Homework Statement A DC current is flowing between two electrodes through a iron disk medium. Positive is attached to the copper shaft of the disc and the negative is attached to the outer brass periphery of the disk. The radius of the disk is 2,54mm (1 inch) and the height of the disk is 1cm...

Homework Statement There is a magnet that approaches the loop as in the figure. There is already a counterclockwise current in the loop. What happens to the current in the loop? Is my reasoning correct? Homework Equations The Attempt at a Solution Since the flux is increasing in the loop...

Homework Statement I have a current source of 2mA in parrallel with a resistor of 9.2kOhm and a short. What is the current through the short? Homework Equations The Attempt at a Solution I always thought shorts had an infinite amount of current but maybe I do not quite understand the...

Hi there, I was recently helping a friend of mine with a fairly standard electromagnetic induction problem (a basic sketch of the set-up is attached) where we have a current loop with resistance ##R## moving through a magnetic dipole and had to roughly sketch out the current induced in the loop...

Hi all, I was working the following example: where I need to find the currents. I tried solving using the traditional V=IR => I=V/R, and then I tried with the current division rule. However with the current division rule the answers don't match. Also according to the answers on the book the...

[ mentor note: post adjusted to conform to homework template and some spellings fixed ] 1. The Problem I have some few questions that connect voltage, current and resistance. Imagine that we have a circuit that consists of a battery (5V), 2 resistors. Now once we close the circuit, battery...

I'm trying to go through chapter III of the vol.8 of Landau and Lifshitz series. (Fortunately the book is uploaded to the archive.org, I guess it is in the public domain.) At page 87 ( << Archive.org link deleted by the Mentors because of copyright violation >> ), they speak about the Joule...

I have wondered if there is a symmetric current configuration that gives the magnetic field of a half-infinite solenoid. With some thought I think I came up with such a configuration of current loops that produces the same magnetic field as a half-infinite solenoid Suppose we have a large but...

When I was an undergrad doing research in a university lab, the director of the lab also consulted at a Nuclear Fusion company. I remember like it was yesterday him making a statement that commercial Nuclear Fusion was going to be a reality within 10 years. That was 1977. What happened? Lack...

Sorry if that title doesn't match up well with my question. I think it captures roughly what I'm wondering about. My uncertainty is to do with how much of mathematics is certainly true. Like, if I picked up any undergrad or grad textbook in mathematics, would everything in it be true based on...

Why is the current of the boundary uniform?

Hi, This is a general question: Do the motor constants KV and KT stay constant at high current? Thanks

Homework Statement In the circuit diagram shown , Xc = 100 ohm , XL = 200 ohm , R = 100 ohm , the effective current through the source is ? Homework Equations Z= √( R^2 + ( XL - Xc)^2) Vrms = Irms/ ZThe Attempt at a Solution I tried to draw the phaser diagram and calculate the relation...

Hello friends... I'll jump right into the deal here.. I pranked a friend by putting a raspberry pi into a yoda head like the one on his desk. There's an intro video: and the prank itself: if you are intrigued. Everything in the head runs off 3 AAA batteries. 1 raspberry pi zero w, 1 small...

Homework Statement In the given circuit at t=0 S is closed then at time t, i1/i2 a) is constant b) increases c) decreases d) first increases then decreases Homework Equations V=IR, Q=CV The Attempt at a Solution At t=0, capacitors act like closed switches, so I2=2I1, where I2 and I1 are the...

Dear Sirs, If I take this explanation as being true "The heat is generated on the microscale when the conduction electrons transfer energy to the conductor's atoms by way of collisions." So a "current" must have a quantum of kinetic energy going into the conductor (resistive element) and a...

Homework Statement Homework Equations CMRR = Av/Acm Acm= Δ/R , Δ = (2 x Tolerance of Resistor).R The Attempt at a Solution I have to admit I am a bit confused by the premise of the problem. My understanding is Vout is used to vary Vcharge in some way, so that Icharge is always 1.3 A. Then...

There is current flowing in a wire. An observer at rest with respect to current, says there is a magnetic field (B) around wire, due to current, I. [Biot-Savart law]. Now switch to someone moving at the speed of current. The current appears stationary to this someone. Therefore this someone...

I often get confused that why we have to use the ancient idea for the direction of current flowing.I have come to know a very weak reason for it.It is said that when current was first discovered,it was assumed that the current flows from the positive region to the negative region(using the idea...

Homework Statement A typical monthly utility rate structure might go something like this: $1.60 for the first 16 kWh, 7.05 cents/kWh for the next 34 kWh used, 5.02 cents/kWh for the next 50 kWh, 3.25 cents/kWh for the next 100 kWh, 2.95 cents/kWh for the next 200 kWh, 2.35 cents/kWh for all in...

Homework Statement As the title suggests, I have a school project where I’m supposed to design a hand shake flashlight using AWG 34 copper wire, a niobium cylindrical magnet, hard paper (sort of like cardboard), and a red LED. The goal’s to get the red LED to light. My teacher gave some hints...

Homework Statement Homework Equations 3. The Attempt at a Solution [/B] Currently working on the question relating to the ground current on the voltage regulator, 7805 (data sheet included below) I am very much unsure what to calculate here I'm assuming the current to ground is the input...

Homework Statement Please help me answer thew question in the image.[/B] Homework Equations Current Density J=conductivity X Electric field[/B] The Attempt at a Solution As the current density depends on the conductivity of the material through which the electrons constitutuing it are...

I've seen a documentary about the Yukon Route Railroad. Some trains are run by old steam engines (with Diesel). They also equipped their engines with eddy current brakes and said, that the resulting current is conducted into resistors and via thermal energy removed into air. I assume that...

The 2 Ohms on the voltage source is its internal resistance, what is the current flowing through the (0 Ohms) Path?

Assume resistor R/heated segment is 5 Ohms, while the path in the right hand side remains 0, thus, total resistance is 0 Ohms, my question is how could current be induced if potential difference is 0(due to zero total resistance) Or is it probably because of the batteries internal resistance?

Homework Statement We have a circular loop of wire, with AB is another wire which is also the diameter of the circular loop. The direction of magnetic field is perpendicular to the loop, into the plane of paper. The magnetic field strength is decreased at a constant rate, without changing the...

Homework Statement Seven equal resistors, each of resistance 2Ω are connected with a battery of 3V in a circuit shown. If i1 is the current when the switch S is open and i2 is the current when switch S is closed, find the value of i1/i2. Homework Equations 1)Equivalent resistance formula...

I've seen answers saying that electricity takes path of least resistance, I know this and there is no need to explain this for me. A forum's answer told me that the electrons initially flow through to the path with resistance and eventually becomes congested (redirecting the remaining electrons...

This i a test question and we are not allowed to use a calculator, so I was wondering whether I did everything correctly, since the I1 = - 1/7. I am supposed to find out I3, but stopped at I1, since the result is a bit tricky. 1. Homework Statement R1 = 10 ohm, R2 = 20 ohm, R3 = 40 ohm I3 = ...

Homework Statement [/B] State and explain whether or not current will flow through the lamps in these circuits Homework Equations None The Attempt at a Solution I am confused with figure 6 as my explanation is different from my textbook's answer. My textbook says: "Figure 6 – the lamp is...

Homework Statement Homework Equations [/B] V = 1/L di/dt I = Io x (1 - e^(-t/L/R) Tau = L/RThe Attempt at a Solution [/B] Ii = 0mA ; If = 1mA Vi = 1V ; Vf = 0V Tau = 15uH / 1k Ohms = 10ns If my above is correct, then voltage and current equations through inductor should be as follows...

To put this in another way, is there some reason from first-principles as to why we have j as the spatial component of the four-current rather than the total current density which includes the displacement current? Has anyone tried to see what the experimental consequences of this would be? Kevin M.

Homework Statement The figure below shows a small circular loop of wire in the plane of a long, straight wire that carries a steady current I upward. If the loop is moved from distance x_2 to distance x_1 from the straight wire, what will be the direction of the induced current in the loop and...

Homework Statement [/B] Calculate, and plot along with (on the same plot) the voltage seen below, the current flowing in the following circuit using the integral relationship between the voltage across an inductor and the current through the inductor. Verify your hand calculations and plot...

From what I've read, it says that high current is dangerous. So my question is if you had 1v and 10amp, would it be more dangerous than 10v and 1 amp? Shouldn't they be the same? Why don't we say high watts are dangerous?

Hi to everybody! Please: can you help with this problem? A conductive disk with a radius a = 20 cm, with negligible moment of inertia, rotates around its horizontal axis. The disc region around the radius is inserted in a magnetic field B = 0.75 T perpendicular to the disk itself. A mass is...

A cable of resistance 12 Ohm carries electric power from a generator producing 250 kilowatt at 10,000 volts. Calculate the current in the cable. Solution using P=VI I=25A but using P=I^2R 250000=I^2×12 I =500/root 12 Amps What is the reason for the different...

In order to check if a quantum particle crosses a barrier or not, isn't calculating ##|\psi(x)|^2## enough in that particular region ? Why do we need to calculate probability current density for that matter?

Hey guys, in the picture below, the current flowing through R1 is the same flowing through R3 right? And hence we have R1 and R3 in series? In this second picture R2 is going to cancel out because apparently that's what happens when you have a branch containing components parallel with a wire...

Hello, We just finished up midterms and I actually did well--got an A. However, somehow between the midterm (class before last) and last class we jumped to creating a circuit with a diode. I am pretty lost. 1. Homework Statement Homework Equations Voltage / Current = ResistanceThe Attempt...

What is currently the common opinion on Chronology Protection manifested by Hawking almost 30 years ago? There does not seem to be any fully accepted no-go result for Thornian time machines. Energy conditions can be violated in QFT, semi-classical results suffer from counter-examples, Novikov's...

I want to start by saying that I'm in no way trying to say that Dark Matter isn't a real pehonomenon in space. I also have no intention to sway one way or another. However, I feel like most scientiests are swaying towards the 'dark matter' is some kind of WIMP or such. It's much easier to read...

I am performing an experiment where I have built a scale model of a wind turbine, and am measuring the current it can produce with a micro generator. I am using a standard multi meter and the micro generator is DC. I do not know much about the topic, but whenever I start measuring the current...

If I have 120 vac power cord and I wrap a coil around one of the conductors, will a current/voltage be produced in the coil? If so what are the equations that could be used to characterize this arrangement? I.e., how many coils, what size wire, etc. To produce a certain voltage in the coil?

Homework Statement I have a coaxial cable with internal conductor of radius r1 and external conductor of radii r2 and r3. The material of the conductors has a conductivity ##\sigma_1##. Between the conductors there is a imperfect dielectric of conductivity ##\sigma_2##. Consider the...

I had a test today on my linear algebra class, and it's safe to say that I didn't get more than a seventy percent on it. I got the first two problems of the test down, but the last problem asked me to prove something involving linearly independent sequences, how if a vector isn't in the span of...

If two light bulbs have the same voltage but one with a lower current does it make one dimmer than the other? I’m confused why lights in parallel circuits don’t get dimmer even tho there is less current. Thx for replying

How can I get around current limiter of this buck-boost converter to achieve a lot higher current output than max rated current output for a very short amount of time ? Does having high continuous current discharge power source at the input help it in any way ? This buck-boost converter offers...