Current Definition and 1000 Threads

In 1979 Alan Guth came up with the theory of cosmic inflation. A mechanism by which a proposed field named the inflaton would give rise to a period of massive expansion brought on by quantum fluctuations eventually bringing about the uniform distribution of matter in the universe that we see...

Homework Statement Two thin conducting spherical shells have radii R1 and R2.Outer shell is charged to q and inner shell earthed.Find charge appearing on both the shells. Homework Equations The Attempt at a Solution Isnt the charge on inner shell 0 and charge on outer shell remains Q as it...

Homework Statement A voltage of V = V_0 sin(\omega t) is applied to an inductor. Find an expression for the current and hence the power. Homework Equations I have used the equation: V = -L \frac{di}{dt} and for power: P = IV The Attempt at a Solution I tried to find I(t) by integrating...

When using the Mesh Current Method and you encounter a loop with a current source that is going opposite to the mesh current do you write it down as a negative current source?

Two batteries connected in series feed a 0.16 Ohm resistor with 80 Watts of power at 3.85 Volts. Each 4 Volts battery is capable of supplying up to 20 Amps of continuous current. Ohm's Law calculation gives 22.36 Amps of current draw for the entire circuit but ... Question 1: How much current...

As the picture showed, when I assigned a current excitation on the coil plane( pink one in image), Ansoft Maxwell alert ”current1 can not assigned on the entity of type face". This is incredible as I take the process completely based on the book!

If a motor slowed to a halt, will the current go up or down

If I have a magnetic field describing a closed path it means that this closed path is surrounding a current, right? But if I have no current, is it the displacement current ? I'm thinking of a magnetic dipole, its magnetic field describes closed paths from its north to south pole, so is there a...

As medulla is hyperosmotic with respect to medullary collecting tubules (I.e. main site for water absorption )water flows out of the collecting tubules and urine get concentrated ...But how it enters vasa recta since vasa recta is also going through same hyperosmotic medulla ,how it absorbs...

I had a question in my textbook asking why is the magnetic field generated by the displacement current in a capacitor more difficult to be measured than the magnetic field generated by the current in the wire. But I don't know how is this type of magnetic field measured, I only know that they...

suppose there is a cavity inside a current carrying conductor.if anyone is inside the cavity he will be electrified or not?what's the explanation of this problem?

Homework Statement Discussions of the possibility of a tangential E-field external to a current-carrying conductor must include a voltage source and a return path. Here the problem is reduced to (we believe) the simplest possible geometry. Assume that a circular conducting loop has constant...

I have a elctromechanical contactor (contactor is an electrically operated switch - It is larger version of relay) which has following specification, Inductive full load current - 30A Resistive full load current - 40A Why is rated inductive current less than rated resistive current?

How would I be able to produce a circuit that produces a very high current at a very low voltage? Would it be considered a reverse Tesla coil?

Let's say we have a basic electric circuit consisting of a battery with some potential difference, and a loop of wire. The wire loop also has some segment with a higher resistance. Now since there is a potential difference, the free electrons will move to make the circuit equipotential. The...

Homework Statement [/B] ∇ * B = 0 and ∇ X B = Mu * J. This is proved to hold not only for infinite wires but for magnetostatics in general. Magnetostatics = steady current Closed wire loop with constant current is certainly a magnetostatics example. Magnetic field on z axis above loop around...

Homework Statement From an original surface current ##\vec{K}=K\hat{\phi}## on a finite solenoid, I got ##\vec{B}=\mu_{0}Kf(z)\hat{k}##, for ##r<R##. Assuming that ##\vec{K}## now slowly oscillates in time such as: ##\vec{K(t)}=K_{0}\cos\left(\omega t\right)\hat{\phi}##, so that I still can use...

when in LC oscillation current flow from inductance to capacitor and charge is opposite polarity. why don't current flow in reverse of it and charging the capacitor in same manner as it was earlier.

when a square loop is stretched to make a rectangular or circular loop(wire length remain same) in uniform magnetic field into the plane of paper what could be the direction of induced current. please share explanation as well

Homework Statement The diagram of the electric circuit, the problem statement (and an attempt) are included in the file below.: https://www.docdroid.net/RD0ZEgA/question-3.pdf Homework Equations Dependent Current Source Nodal analysis Short Circuit Current Thevenin Voltage Thevenin...

Hi lads, I couldn't find this info on Google... Are the Heart and Brain the only organs which physiological functions are based on electrical impulses? What happens if we apply electrical current through other organs? Thanks

Homework Statement I have 4 resistive sensors thus I need to tie 4 floating current sources. Floating current source will give me output voltage linear to the resistance of a sensor. I know it is not the best solution but it is good enough. Image provided: Homework Equations None The Attempt...

I am confused by the definition of current density in Maxwell electrodynamics. Perhaps someone can help me out? As I understand it, the current density function can be written as $$ \vec{J} = \rho \vec{v}_S$$ where ρ is the charge density function and v_S is the continuous source charge...

Homework Statement A certain commercial mass spectrometer is used to separate uranium ions of mass 3.92 multiplied by 10-25 kg and charge 3.20 multiplied by 10-19 C from related species. The ions are accelerated through a potential difference of 100 kV and then pass into a uniform magnetic...

An electric current in a wire occurs when... A. electrons move in the wire as a result of getting pushed along from a neighboring electron. B. electrons move in the wire as a result of the repelling force from the negative battery terminal and the attractive force from the positive battery...

<<Moderator note: Political statement removed.>> To protect against a nuclear EMP (NEMP) usually a big metal box is used, which is electrically connected to earth, to discharge the electrical pulse. Most houses in europe have a 3-grid electric system, L, Neutral (N) and Protective Earth (PE)...

Hello, I've been googling about this topic and have read from a number of different books but I still haven't found an exact answer to my question. It is known that the current is equal when the resistors are in a series. But the resistors per definition reduce current flow. If there are 2...

Hi, I studied the Maxwell laws and the Biot Savart law and I found something I cannot answer. If you have a finite wire carrying current (let say 5m long) and you want to determine the magnetic induction vector due to it at some point that has distance r from the wire, you have 2 options I...

OK, so my last post seemed meaningless. Can anyone help with this, I understand some of you say current moves from the positive terminal of a battery to the negative terminal and some say the opposite. Lets say it is positive to negative just for this question. If I have a battery that the...

I measure sound (dB) from a speaker at 0cm and 100cm using a diaphragm microphone. 0cm-100dB, 100cm-30dB diaphragm microphone cinsists of a diaphram, coil and a permanent magnet. the coil is attached to the diaphragm, when a sound wave hits the diaphragm it causes to move back and forth which...

I know that the right hand rule applies for induced currents, and the left hand rule is for motors, but why? It doesn't seem to connect with any other physics laws and is very counter-intuitive that the current will flow in one direction rather than the opposite direction if both are...

Homework Statement Homework EquationsThe Attempt at a Solution I am having a little doubt as to how to think of the moving electron as a current . I am considering the moving electron as a very tiny (infinitesimal ) current element . It is as if when the electron is at A , there is a very...

For a Year 12 Assignment I have to do a seminar on how magnetic fields are involved with a certain topic. I chose nuclear fusion energy production and specifically the tokamak. I understand that a toroidal magnetic field is created when a current is sent through a solenoid wrapped in a torus...

Homework Statement Homework EquationsThe Attempt at a Solution The photoelectric current is directly proportional to the intensity of the light falling on it . It will not depend on the focal length of the lens . When the lens of half the diameter is used , intensity is halved . This...

Homework Statement Homework EquationsThe Attempt at a Solution The magnetic field lines due to the infinite wire will be clockwise .When P is the midpoint of the magnet , Magnetic field at the South Pole will have a component upwards and a component towards right .This means S will...

https://imgur.com/a/Yb2vpmp why can the inductor be treated as a 1A source?

Trying to create an experiment that utilizes a motor driven shaft to measure the angular velocity of another shaft via eddy currents. We made a mock experiment that uses 8mm shafts, pillow bearings, and ceramic magnets from home depot, but don't see a torque on a non-ferrous metal attached to a...

Homework Statement [IMG]http://[url=https://ibb.co/b3Emfo]https://preview.ibb.co/gLaEY8/20180527_055248.jpg[ A conducting bar slides down without friction on a pair of conducting rails separated by distance d. Connected to resistor R and there magnetic field B directed upward, perpendicular to...

Homework Statement The capacitor is changed so that the largest possible current is supplied by the source. Enter the value of the capacitive reactance when this change is made. Give your answer in Ohms (Ω). A unit is not required with your answer. Homework Equations The circuit is powered by...

The kinetic energy of electrons in a conductor is roughly 9 orders of magnitude greater than the kinetic energy from the drift velocity of the electrons. It seems that the kinetic energy from the drift velocity is not enough to account for the heating, where does the heat energy come from? Cheers

Homework Statement In the circuit shown in the figure each capacitor initially has a charge of magnitude 3.60nC on its plates. After the switch S is closed, what will be the current in the circuit at the instant that the capacitors have lost 80.0% of their initial stored energy? the shown 3...

Homework Statement Homework EquationsThe Attempt at a Solution First I will label a few points . A is the point on the ring touching the rails , vertically below P . B is the point on the ring touching the rails , vertically below Q . T is the topmost point on the ring . M is the bottommost...

Homework Statement Homework EquationsThe Attempt at a Solution For calculation sake I will consider R = 1Ω . Final answer will be in mA instead of A . The middle two resistors 3R and 4R are in parallel , so I consider their equivalent resistance 12R/7 in the middle branch . In the left...

Homework Statement This is a multi choice question from last years aqa a level. We know a positive reading is produced on the scales indicating something is pushing down on the scales. Please see the picture. Homework Equations We know current direction, not B field. The Attempt at a...

Homework Statement Homework Equations Current cannot change suddenly through inductor unless input is impulse voltage source. The Attempt at a Solution since input is DC source we have i(0+) = i(0-) so we have di/dt at t = 0+ is 0. Is it correct? Book has mentioned answer as B which is weird...

Hello, I have a simple question regarding current flow through a common part of a circuit. I encountered this as I am reading "Code: The Hidden Langauge of Computer Hardware and Software" by Charles Petzold. The images I've attached display what I'm talking about. I'd like to know if there's a...

Hello. Say I have a high powered device that draws continuous 18A. 3.7v And I have one 3.7v 3500mah 18650 with a maximum continuous discharge of 10A, I know the battery will overheat and will most likely get damaged or shorten its life, or even catch fire. But If I have another battery (same...

Homework Statement In the circuit shown,the initial charge on the capacitor is Q0 = 200μC . If the switch is closed at t=0 , the capacitor starts discharging through the resistance R=4MΩ . What is the initial current (in μA) (i.e. at t=0) in the circuit? Homework Equations I = I0 e-t/τ τ =...

Homework Statement I'm asked to find the voltage, current, and resistance through each resistor in the given circuit. Homework Equations Req for parallel = 1/R1 + 1/R2 + ... Req for series = R1 + R2 + ... The Attempt at a Solution First, I want to find the total resistance in the circuit...

Homework Statement A long straight solenoid of cross-sectional area 400 cm^2 is wound with 10 turns of wire per centimeter, and the winding carry a current in the direction shown (downward). A small ring of radius 5.00 cm and resistance 0.300 ohms is placed at the center of the solenoid. If the...