An electric current is a stream of charged particles, such as electrons or ions, moving through an electrical conductor or space. It is measured as the net rate of flow of electric charge through a surface or into a control volume. The moving particles are called charge carriers, which may be one of several types of particles, depending on the conductor. In electric circuits the charge carriers are often electrons moving through a wire. In semiconductors they can be electrons or holes. In a electrolyte the charge carriers are ions, while in plasma, an ionized gas, they are ions and electrons.The SI unit of electric current is the ampere, or amp, which is the flow of electric charge across a surface at the rate of one coulomb per second. The ampere (symbol: A) is an SI base unit Electric current is measured using a device called an ammeter.Electric currents create magnetic fields, which are used in motors, generators, inductors, and transformers. In ordinary conductors, they cause Joule heating, which creates light in incandescent light bulbs. Time-varying currents emit electromagnetic waves, which are used in telecommunications to broadcast information.
A wire coinciding with the X-axis carries a current I1 in the direction of increasing x. A second wire is parallel to the Z-axis at a distance R, and carries a current I2 in the downward direction as indicated in the figure. The magnetic field at point P (0, 0, R) is: (options and diagram in photo)
In this video at 0:38 man say that unbalance current flow increase magnetic radiation far away, even few streets away from source..
1. Why radiation increase in these situation?
2. Is every system subject to that phenomenon and when unbalanced current happend?
3. Will emf meter show this...
In this situation I would have two solenoids facing each other, such that both ends are north for example, and when activated they are actively experiencing repulsion, I know that the magnetic field of both would decrease in strength, but would there be any affect on the electrical input of each...
According to the special theory of relativity the electric and magnetic fields observed from a charge distribution should depend on the relative motion of the observer. For example consider a linear arrangement of point charges which are fixed relative to each other. An observer who is...
Image from Wiley Intro Physics Textbook sample problem
This was the given problem. In the diagram, one can see that the current flowing into each battery equals the current flowing out of each battery. Is this always the case, and why?
If there was only one battery, I guess it could be...
This post is somewhat of a continuation of this other post. I would like to better understand induction and be able to link the electrical equations with Newton's.
For reference, this is a paper about the Eddy Current Damper I would like to study first.
I think these components are very well...
This is the proposal, except the two middle voltages are 110V, not 12V.
Say the max switch-on inrush current of XFMR1 is xA with the secondary open, would the value change significantly in the above arrangement, with the secondary of XFMR2 open?
1. Consider this diagram. Does the bulb light up? The equation I=V/R tells me no, but if there is a potential difference between the two points, surely current will flow and the bulb will light? As there is nowhere for the electrons to go, I assume it will only light for a very short period of...
Suppose the ring is held stationary such that its area vector points upward. The magnet moves downward toward the ring at constant velocity north-pole first. (The starting position is shown in the figure.)
Since ##\vec{B}## is downward while ##\vec{A}## is upward, ##\Phi_B=\vec{B}\cdot\vec{A}##...
(1) https://www.youtube.com/results?search_query=relativity+and+electromagnetism
(2)
If I understand this correctly, then, well, shouldn't all current-carrying wires exhibit a small amount of positive charge?
I recently heard the narrator of a podcast state that the current of almost all rivers in the world flows from North to South. The narrator said the Nile River is one of very few rivers in the world that flows from South to North.
I cannot figure out why almost all rivers in the world have a...
I assumed that the radius is referring to a major R like in the image below.
I plugged all the values (except for length) into the equation B = µ*N*I/2πr to get 155.6 A for the current value. I am unsure if this is the correct value or if radius refers to minor r of solenoid, in which case a...
The following circuit is:
Going clockwise the current ##I_1## goes through resistor ##R_1## and voltage ##V_11##. Current ##I_2## goes through capacitator ##C_1## and ##R_2##.
Current ##I_3## goes through resistors ##R_3## and ##R_4##. Current ##I_4## goes through resistor ##R_5##, but from...
A wire loop accelerates from position 1 to position 5. It enters an area of a homogenous non changing magnetic field B. Rank the induced currents in the loop starting from the biggest. in solutions it says I4>I2>I1=I3=I5=0 but i dont understand why
I want to know the difference between the two circuits below , and Why don't I bundle both batteries into one 24V battery?
pls help me in this .
This is the original circuit:
And to merge the two batteries , What is the resulting value of a battery resulting from the merger?
I thought...
If we connect an inductor without ohmic resistance to the alternating voltage source, voltage should induce in the inductor because of the Faraday's law. Voltage is induced by changing magnetic flux through the inductor which is accomplished by alternating current through it. Therefore, in order...
The solar irradiance incident on the PV modules is 5 kwh/m^2-day.The current each module can provide is 5 A and the voltage due to the separation of charge carriers is 18 V under standard conditions (1 Sun=1000 W/m2) so we would have to connect two modules in series to exceed the voltage of the...
I found the time constant using L/R and got 0.62s (3.6H/5.8ohms)
I found the initial current V/R and got 4.086A (23.7V/5.8ohms)
I(f) = 4.086A(1-e^(-0.5s/0.62s))
Then I plugged it into the equation and got 2.26A and it was wrong
Imagine a very large disc with current converging to it's center as $$ I=- \frac{k}{r} \hat{r}$$
Obviously ##\theta## is absent in the equation so the magnetic field by this current should look the same no matter which angle one is observing. Then does this mean that the magnetic field is...
The current in a wire is said to produce a magnetic field and a force on a charge. It is said that the correct way to interpret the effect is because of relativity. So does that mean that that the most basic non-relativistic equations that offer basic calculations of the forces and fields are...
good morning gentlemen, I would like to ask you a fairly simple question but which I am unable to resolve. Then considering the "skin effect", which involves an increase in resistance to the passage of current with consequent generation of eddy currents, this leads to an accumulation of charges...
Hi all,
playing with fancy e textiles and I wish to run a current through it. I don’t want to use mains, or d cell batteries. Can you point me in the right direction what components I could use and also how to get away with any grounding as it’s just a small area to put a current through...
I tried splitting it up into 4 individual resistors, adding them up (each side serially and then both sides with each other as parallel) and then using V=IR but it ended up being the same current as the original.
(The answer should end up being (9/8)* the original current)
I know that Ohm's Law gives me the answer of 0.25 A but what I don't understand is how is it ok to use Ohm's Law when I know that the lamp doesn't obey the law? I know that as the current is increased through the lamp, the resistance increases due to temperature rise which, I am told, makes it...
Battery Capacity = Current * Time
Power = 400 * 750 = 300000 Watts
V*I = 300000
I = 300000/300 = 1000 Amps
Battery Capacity = 1000 * 1 = 1000AH. Are the calculations correct? Why the battery capacity is defined in Amps?
Hi,
Let's say we have a basic AC generator, where a single wire is rotated within two magnets:
Due to the electromotive force, a voltage is generated so that Va - Vb = 120V.
Let's now ground Vb side directly to earth, while leaving Va still open:
We can say that Vb = Vc = 0V and Va...
Playing around with electricity and magnetism. Well, trying to anyways. Wound some wire up and down the length of a 4" screw several times. Thought when I spun the magnet close to the coil I would get a detectable amount of current on my voltmeter. Anyone know why I'm not reading anything? I...
Can someone explain what exactly happens at (4) ? I do not clearly follow, except that there is some cosine law going on?
I also do not really understand why at (3), r' doesnt have a z hat component, but I can live with that.
So here is my dilemma. I have a test setup with multiple coils all lined up in parallel in such a way that one end of each coil is connected together while the other is connected to a switch (mosfet) the switches then connect each coil to ground but that ground can become + based on which coil...
How should I calculate the angular momentum carried by a current carrying circular wire? Is it correct to consider the angular momentum of the electrons moving with drift velocity? Like
##L = n m_e v_{drift} r## where ##r## is radius of the loop, and ##n## is total number of electrons moving in...
Hi,
I am not sure if I have calculated the task b correctly.
I always interpret an open switch as an infinitely large resistor, which is why no current is flowing through this "resistor". So there is no current in the red circle, as it was the case in task part a, but only in the blue circle...
Suppose the switch has been closed for a long time so that the capacitor is fully charged and current is constant.
a)Find the current in each resistor and charge Q of the capacitor.
b)The switch is now opened at t=0s. Write the equation for the current for the resistor of 15kΩ as a function of...
Following the Picture below,
If I Conduct current through Permanent magnet Bar and hold the battery still. Will the magnet move in any direction ? Thank you.
There has been an explosion of discussion among experts about the evolving/growing dangers of AI and what to do about it. This debate has gone public, largely due to the recent success of generative AI, and the rapid pace of improvement. As an example, AI models which can generate images based...
It shows 0 and it's obvious why. I have another question.
Can I say that in this circuit the current is maximum and it equals to ##\frac ε r = 2A##?!
Someone asked me this question:
Are A and B two ends of the wire? If yes, Why is there current in the wire even though the potential difference...
I need help with part c.
My solution:
Is there an other way to do this other than dimensional analysis?
P.S "dr an infinitesimal radius", it ofcourse should be dz.
The recent spate of train derailments has put the spotlight on derailments and railroad safety in general.
Railroads are generally a safe means of transporting cargo, including hazardous chemicals, and in fact railroads are safer than a decade or two ago. Yet, one catastrophic accident...
First I solved 4+j3, which I squared 4 and 3 to equal 16 and 9 then I added them to get 25 and then I got the square root of 25 = 5.
Then I plugged it back in to the equation.
[50/(5)(50)+100] x 150 to get 50/350x 150= 1/7(150)= 21.42. I've attached the correct answer.
After the switch is closed, current flows clockwise from the battery to resistor R1 and down through the switch.
I don't understand the reasoning for the following: the current from the capacitor flows counterclockwise and down through the switch to resistor R2. How do I determine the direction...
The operation of a transmission line is based on the axial propagation of electromagnetic waves between the two line conductors. However, the study of the transmission lines does not focus on E and B waves but on voltage and current waves.
It is considered that there are resistance...
I have taken portions of a schematic for amplifying the current I1, this I1 current is the phase current from one of the legs of the inverter. The output vout1 is the amplified voltage, again given to a micro which has internal opamp. Is my circuit understanding correct?
When I give I1 = 10...
What is the very common culprit component and what is its
function within SMPS having weak current, far weaker than its rating while its voltage is always perfect?
3 A+ 2 A = 7 A+ I
I = -2A
How the current can be in negative direction? If the sign if negative, doesn't it mean that the current will move towards the point P? Also If I am taking the 2A to be positive then Kirchhoff's law isn't satisfied as 5A≠7A
We producing industrial steam boilers. We also produce snail fans for our boilers. The problem is our fan blades are a little bit heavy for our motors until blades get warm. "We can't use more powerfull motors cause of energy saving." We control our fan motors via drivers and our fan blades...