All Questions
Tagged with electromagnetic-induction magnetic-fields
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Faraday Induction Experiment question
I’m trying to understand the basic physical laws applying to Faraday’s induction experiment as pictured below. The Wikipedia site doesn’t go into detail.
When the smaller diameter inductor is inserted ...
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2
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INDUCTANCE depends on the number of turns in a solenoid. Is this the case with RELUCTANCE as well?
The total flux ($\Phi$ ) through an solenoidal inductor of length $l$ and $N$ turns is proportional to the current through the inductor and the inductance $L$ of the inductor according to
$$\Phi =L \...
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Is the induced electric field in a current changing solenoid actually that what we call magnetic vector potential field?
Induced electric field $E$ in a changing current (i.e. changing magnetic field $B$) solenoid
image creditis: https://faculty.uml.edu//Andriy_Danylov/Teaching/documents/L18Ch33InducedEcovered.pdf
I was ...
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How to reduce magnetic field between two magnetic shield sheets (silicon steel sheets)?
I put 2 parallel silicon steel sheets between magnetic field as below:
As silicon steel has much bigger permeability than air,magnetic line will go through 2 silicon steel sheets.
What I can do to ...
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Modeling the Effect of Magnetic Induction on Single Neurons
In this paper, the authors suggest a potential mechanism for magnetoreception in birds: as the Earth's magnetic field (taken to be homogeneous over sufficiently small spatial scales) passes through ...
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Would a ring magnet around a copper tube be slowed?
if a ring-shaped magnet was dropped with a copper pole through the center would it be slowed the same as a cylindrical magnet in a copper tube? if so would it be slowed more or less?
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Magnetic flux through a closed surface
I was reading Electromagnetic Induction, then I faced a understanding problem while reading the integral and differential form of Faraday's Law..
We know Magnetic Flux= ${\bf B} \cdot {\bf S}$
Where ${...
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2
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Is Farady's law valid for conducting loop only? [duplicate]
Is it applicable to a nonconductive loop? What if the loop consists of both non-conducting and conducting paths?
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Electron in varying magnetic field
Lets consider an electron that is placed in an existing, constant in space near the electron, magnetic field. Electron is stationary. Magnetic field over time gradually reduces to zero.
I assume ...
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Induced voltage from magnetic field
Suppose we have a surface S(x,y) = x^2-2y for 0<x<2,0<y<5 , and a magnetic field (2t,3t+1,t).
To find the total magnetic flux through the surface S we find a normal vector to S n = (-Sx,-...
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Find the work to move a coil in an uniform magnetic field [closed]
we have a rectangular coil ($d$ and $3d$ wide) in a magnetic field as in the picture.
To the left we have $B_0 T$ and to the right $\frac{B_0}{2} T$.
There is a counterclockwise current in the coil ...
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Fundamental, intuitive interpretation of the magnetic field $\vec{H}$
In many electrodynamics/magnetism textbooks it is stated that the magnetic induction $\vec{B}$ is related to the magnetic field $\vec{H}$ via $\vec{B}=\mu_0(\vec{H}+\vec{M})$. It is then argued that $\...
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Why is mechanical work equal to Joule heating?
This question came about when I was doing a problem related to a conducting loop with resistance $R$ moving with velocity $v$ in a magnetic field. It asks you to verify an expression for the force ...
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Heuristic expressions for the inductance of a finite-length solenoid
The expression for the inductance of a very long solenoid is
$$L = \frac{\mu_0 N^2(\pi r^2)}{l}$$
where $l$, $r$ and $N$ are the length, radius and number of turns respectively. Things get much ...
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How to find the force needed? [closed]
To keep the system in equilibrium, the Fg should equal FBuoyant + FMagnetic. However, I'm having trouble seeing how the FMagnetic would push the tube upwards. We're using conventional current, and the ...
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Nature of force between two permanent magnets
When we put two permanent magnets close to each other they repel or attract each other and this process increase their kinetic energy. I know that magnetic force can't increase kinetic energy so plz ...
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Why does the north pole of a magnet always induce a south pole in the near end of a magnetic material?
If a magnetic material such as an iron bar is placed near a magnet, the former becomes an induced magnet with the end closest to the north pole of the magnet becoming a south pole and vice-versa for ...
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Why difference in magnetic field generate electric current? How is induced electric current generated?in simple words please,I'm a average 10th grader [duplicate]
Why does moving magnet set charges to motion in a conductor?why?why does difference in magnetic field produce electric current? please can someone answer in simple language and not use many technical ...
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Is self-inductance dependent on geometry? Is $\Phi$ net flux or just flux due to cirucit?
Self-inductance of a circuit is defined as $L=\frac{\Phi}{I}.$ But it is not clear what $\Phi$ (read phi) is. Is it net magnetic flux or flux due to the magnetic field created due to current in the ...
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Calculating the magnitude of the force acting on a charge [closed]
A charge of 40 µC moves with instantaneous velocity (v=5×104) j m/s through the uniform fields E=(6×104)(0.52 i +0.56 j +0.645 k) V/m and B=(1.7)(0.693 i +0.6 j +0.4 k) T. How do I calculate the ...
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The variation of induced EMF $\varepsilon$ with time $t$ in a coil if a short bar magnet is moved along its axis with a constant velocity
The variation of induced EMF $\varepsilon$ with time $t$ in a coil if a short bar magnet is moved along its
axis with a constant velocity
tack.imgur.com/hWpO5.png
can someone kindly tell the ...
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EMF induced in solenoid by rotating magnet
I would like to have an equation relating the emf (or current) induced in a solenoid by a rotating magnet with angular velocity $\omega$ and the distance $d$ as shown in the figure.
I really don't ...
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When to consider motional emf and when not to?
In this configuration(given in picture) ,the magnetic flux through the loop is changing(which causes an induced electric field,which causes an induced emf) and for the perpendicular rods AB and CD(if ...
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Can you set up a differential equation for the flux for a magnet falling through a coil?
If you drop a magnet through a coil, the experimental found emf graph looks as follows
Then the flux must have the following shape:
This can be identified as a Cauchy-Lorentz distribution, which is ...
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5
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Total Energy of an electromagnetic wave
This question may sound stupid. But why when we calculate the total energy density (energy/volume), carried by an electromagnetic wave $u_T$, we add both $u_B$ + $u_E$.
Where $u_B = \frac{B^2}{2\mu_0}...
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Electric field of moving charge
Does the electric field of a moving charge (constant velocity) change with time? Or it remains the same?
I know that changing electric fields produce a magnetic field, but in a straight, current-...
user324098
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How is the direction of current induced by the induced magnetic field determined in a metal detector?
In the figure below, from a textbook explaining Eddy Currents, a pulse of current is sent and generates a magnetic field $ B_0 $. The magnetic field produces a change in flux in the metal box that ...
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Force acting on a coil in a magnetic field
so I have been taught that there is no force acting on the bit marked (?) even after if a coil rotates 90 degrees, can someone explain why even after the part marked (?) rotates 90 degrees there will ...
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Electric field in a vacuum
By changing the magnetic field can we generate electric field in a vacuum ?
By the Faradays law of EMI if the magnetic field associated with a coil changes, current is induced in that coil
So if we ...
user324098
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Why is the motion of a copper plate damped when it is allowed to oscillate between the magnetic pole-pieces? How are Eddy currents involved?
Can anyone explain this to me, in simple terms, why the motion of a copper plate is damped when it is allowed to oscillate between the magnetic pole pieces?
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Why isn't Magnetic force doing any work on the rod?
Consider the situation given below :
The rod (of length $l$ and of some resistance "r") connecting the two rails is given a velocity $v$ in the direction shown. Now since this motion ...
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How to calculate retarded potential (for magnetic field calculation) for a group of current carrying loops where the magnitude of current is changing?
For constant current, the magnetic field seems to be easy to calculate because of Biot-Savart Law. For a loop having varying magnitude of current (simplifying an electromagnet), however, it seems that ...
user320191
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Do transformers return current to source when magnetic field collapse at primary coil?
When we close the circut containing an inductor and a battery, the current starts flowing, which builds magnetic field around inductor, changing magnetic field produces its own current in opposite ...
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Why don’t we say that magnetic flux changing with position induces an emf?
As per Faraday’s law of electromagnetic induction, an emf is induced with the rate of change of magnetic flux. But according to one of Faraday’s experiments, relative motion between two coils, or ...
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Can non-conservative fields store potential energy?
I was taught that a time-varying magnetic field generates an electric field which is non-conservative in nature, and my teacher also told me that when a conducting coil is placed in a region with a ...
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Potential in electric field by magnetic induction
There is a point written in my book (S.L. Arora- Simplified Physics Part-1)-
Electric Potential is meaningful only for electric fields produced by stationary charges. It has no meaning for electric ...
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Is Ampere's law or Fraday's Law reversible for AC currents?
In other words, if a time varying magnetic field induce a amount of voltage/current into a coiled wire, would generate the coiled wire that is loaded with the measured/calculated amount of induced ...
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Why is energy in magnetic field dependent upon frame since field is a physical quantity (wave)?
Why does energy in magnetic field change with changing frame. I mean magnetic fields are physical things that are released by source charge. So how can the energy released by a source charge change ...
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If magnetic fields do not have any energy in them then, how could they work on charge?
We know that a magnetic field which is changing and is perpendicular to the velocity of charge $q1$ will create an Electric field which acts upon that $q1$ and does some work. Here the work is being ...
user316791
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How does electromagnetic induction work on an atomic level?
So far I have come to know that changing magnetic field (or flux) creates current. This is also known as Faraday's law of electromagnetic induction. The direction of the current is opposite to the ...
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Deducing the mechanical power necessary for generating voltage in a loop wire
From what I've learned, it seems that by rotating a loop wire inside a magnetic field we can create what's called electromotive force, which can be thought of an analogue to voltage, and it ...
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Repelling ferromagnetic materials with alternating fields
Is it possible, through the induction of eddy currents, to repel a ferromagnetic material using an alternating magnetic field?
Is there a frequency where if one were to spin a strong magnet close to a ...
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Can current be induced by an induced current?
Say there are two concentric loops, and a variable magnetic field.
Due to the variable magnetic field, current is induced in both the loops, but is more in the case of the bigger loop.
So the bigger ...
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Can paramagnetics materials like iron be levitated by a spinning halbech array like aluminium, copper etc?
I know diamagnetic conductors like aluminium or copper can be levitated using a spinning Halbech array as in this video. But can the same work using paramagmetic conductors, specifically iron?
Or will ...
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Is it possible to quantify the tendency for electrons to move between two spatial points for a region with magnetic field present?
It is clear that a potential function can not be defined in presence of magnetic field and faraday's law only gives the expression for EMF over closed loops. Such a thing as EMF between two point is ...
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What is the emf in this circuit?
There is an infinite solenoid with radius $r$ inside the first loop powered by a current that changes over time so that the magnitude of the magnetic field inside the solenoid is $B(t)$. According to ...
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In an electric circuit in a magnetic field, Would we consider the induced emf produced by changing of magnetic field in calculating potential diff?
Change in magnetic field creates a non conservative Electric field and while potential difference is used in conservative field only so...
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Superconducting rod moving at a constant velocity in a uniform magnetic field
A conducting rod moving in a uniform magnetic field with a constant velocity is used as an example in textbooks, with charge moving from one end of the rod to the other and the amount of charge ...
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Magnetic Charge through conducting loop
There's a problem in Griffith's book that I don't understand his solution :
Here's the solution :
What's the justification for $\varepsilon = -L\frac{\mathrm{d} I}{\mathrm{d} t}$ ? $$$$
This ...
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Proving that flux contribution due to rotation is zero for a triangular loop welded to infinite wire set up
Consider a triangular loop attached at the vertex to an infinitely long wire which has time varying current flowing in the +x direction
Adapted from JEE advanced paper-1 2016
One may find that the ...
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