# Questions tagged [electromagnetic-induction]

This tag is for questions regarding to electromagnetic induction, a process in which a conductor is put in a particular position and magnetic field keeps varying or magnetic field is stationary and a conductor is moving. Electromagnetic Induction was first discovered way back in the 1830’s by Michael Faraday.

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### Emf in stationary conductor located in a uniform magnetic field, when the source of this field moves relative to the conductor

When a conductor moves with velocity $\vec v$ in a uniform magnetic field $\vec B$ produced by a stationary source, then the magnetic force in this conductor push charges from one end of the conductor ...
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### Are the accelerated charges the real reason for the magnetic induction? [closed]

I have watched an explanatory video from YouTube that stated that the real reason for the "magnetic induction" are electric field lines of an accelerated charge, that have a component in the ...
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### Back-EMF in a DC motor as a Sine Wave?

I am taking time to re-familiarize myself with the design and principles behind the operation of dc motors. I am right now trying to understand back-emf. Forgive me if I seem to have a piecemeal ...
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### What is the electric field inside an inductor?

In a simple LC oscillation a charged particle was kept in the centre of solenoid ie inductor. At t = 0 will it experience any force? According to me since the particle is in center it won't ...
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### Induced emf and coil winding direction

Recently, I've learned that induced emf is there to oppose the change in magnetic flux. consider a current increasing over time ($\frac{di}{dt}>0)$, moving left to right as it passes through the ...
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### Changing the magnetic field of earth

I am familiar with the concept of toroid which causes an electromagnetic field. Is it possible, if we make a large enough toroid, to change the magnetic field of earth. If yes, then how will it affect ...
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### Will there be magnetic induction between two parallel straight wires and only one of them carrying current?

If two coil is placed parallel and only one of them is conducting the current we can see some current flowing in the other one due to the magnetic flux changing in the current carrying coil. This is ...
1 vote
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### What is the behavior of a magnet floating in a superfluid that rotates indefinitely?

A superfluid has zero viscosity. If a vortex is created, it can rotate indefinitely without any loss of energy. There are objects less dense than a superfluid that can float on its surface, where a ...
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### Induced E.M.F without changes in magnetic flux

When we move a wire upwards through a uniform magnetic field, the magnetic flux does not change. If we consider the equation for magnetic flux which is: ΦB = B ⋅ A = BAcosθ The magnetic field is ...
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### Will the natural or artificial magnets degrades or loses it's magnetic property over time or when used for induction? [duplicate]

Will the natural or artificial magnets degrades or loses it's magnetic property when used for purposes like magnetizing other artificial magnet, generating electricity in wind turbines/hydro power, ...
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### What happens if you isolate an inductor from a live circuit? [duplicate]

Suppose you have a capacitor and you charge it with a battery until it has a voltage V. You suddenly disconnect the capacitor from the battery. As far as I know, the capacitor keeps with voltage V ...
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### Electric field from dipoles

I study from YouTube. The teacher there gave a question (1): And he used the formula $$2E=r\frac{dB}{dt}$$(2) and simply integrated using $dV=-Ed\ell$ along that path in electrostatic conditions. But ...
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Sorry if my Q is simple, I'm still in high school. I'm currently arguing with my physics teacher regarding a Q, shown below. The answers state this. However, I am attempting to argue that the ...
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### How to find permeability of a magnetic material?

I have been working with magnetic materials for quite some time now and never really explored this fundamental parameter. After looking through the literature I realize there and quite few different ...
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### Ampere's law on solenoid, using a circular loop

Suppose we take a long and tightly wound solenoid with current I going in it. We can find the field inside, by ampere's law, taking a rectangular loop and assuming the magnetic field just outside the ...
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### What happens to the charges in an inductor when you induce a voltage?

Say you have two inductors, and - very much like a transformer - you connect the first one to a voltage source, then place the other one close to it, so that there will be an emf induced by the change ...
1 vote
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### Can plasmas have eddy currents?

A couple days ago I asked a question on if plasma could have a magnetic field due to current which was a yes. Now I am wondering again on if plasma can possess eddy currents. Assuming a time varying ...
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### How is a steady current maintained in case of motional EMF if net force on electrons is zero?

I looked at the derivation of emf induced in case of a conducting rod entering a uniform magnetic field perpendicular to it, emf$=Bvl$ if $B$ is the strength of magnetic field, $v$ and $l$ are ...
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### How does the induced current flow? From positive to negative or the opposite?

Let's say there's a rod and it in moving horizontally in a magnetic field (changing flux so current is induced). Using Fleming's right hand rule, we find that induced current flows from left to right. ...
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### Terminal velocity of a bar magnet in a long conducting tube (quantitative)

If a bar magnet is dropped into a copper (conducting) tube, it reaches a terminal velocity. I'm trying to derive this terminal velocity. We know from Lenz's law that $e=\frac{-d\phi}{dt}$. I'm facing ...
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### Isn't the induced electric field vector always tangent to the loop?

In the law of electromagnetic induction: $$\mathcal E_\text{ind}\equiv \oint_\Gamma \mathbf{E_\text{ }}d\mathbf l = -\dot \Phi_\mathbf{B}(t)$$ Here, $d\mathbf l = \hat{\mathbf t}dl$ is taken along the ...
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### Straight wire in moving uniform magnetic field induced emf

My question is a follow-up to this one. The green dotted line is the arbitrary loop which is constructed in the calculation of emf in the wire of length L. x is a variable which can be changed to ...
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### Can a satellite generate electricity by using a planet's magnetic field? [duplicate]

I am entering AP Physics E&M and don't have much knowledge about electricity but always had an idea based on my limited knowledge. If a satellite had a metal coil inside of it, wouldn't it have an ...
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### Faraday's and Kirchoff's in RL circuits

I know this question has probably been asked a 100 times over on this site and there is a whole controversy on it but I still don't understand the explanations and had to ask it again. First of all I ...
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### Growth of Current in an Inductor Connected Across a Battery [duplicate]

When baterry is connected across inductor with no resistance in circuit, won't the current flowing through it be zero, as inductor back emf will counteract the effect of potential difference due to ...
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### Cannot catch a minus sign mistake when deriving the ODE for an LC circuit

It's probably a very basic question but I just cannot wrap my mind around it. I'll just try to derive the differential equation for an LC circuit: According to the law of induction, in a solenoid we ...
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### Effect of catapult field on the weight of magnets

Diagram shows a metal rod, PQ placed perpendicularly to two permanent magnets and connected to an electric circuit. The steel core containing the two magnets is placed on an electronic balance. What ...
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### Why is induced EMF in DC motor being included in Kirchoff's Loop Rule

I was reading some lecture notes (don't think I can include them here) that show the EMF induced in the armature of a DC motor, being included in the equation of Kirchoff's Voltage Law for the ...
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### When a current passes through the secondary of an ideal transformer, KVL is violated in th primary?

When an ideal transformer is on the no load condition, the primary circuit is just a normal AC source connected to an inductor. In other words, the voltage across the inductors equals the source ...
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### Internally, what defines whether a material is magnetically hard or soft?

I know that magnetically hard materials hold magnetic fields (magnetic moment alignment) for longer, while soft metals do not. However, what, internally, causes these properties to arise?
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### Which magnetic field is the one in the inductance equation?

Any self induction problem that can be solved via $emf=-N\frac{\Delta \phi}{\Delta t}$ should be equivalently solvable via $-L\frac{\Delta i}{\Delta t}$. What if the coil is already existing in a ...
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### Voltage measured by a Volt meter on a coil

This question is asked on the 2002 Canadian Association of Physicists Prize Exam: By all logic, the voltage across an inductor in a circuit should be the same as the induced EMF. Or, if there is also ...
1 vote
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### Confused between induced emfs

We know when flux of B changes an EMF is induced in loop And also when a rod moves in mag field Potential difference between its ends is also produced. So is this ques while writing Potential equation ...
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### How does any changing magnetic field induce voltage?

Hopefully the title puts in well enough; a charged particle moving in a magnetic field experiences the Lorentz-Force. If this occurs in a wire and part of the circuit is outside the B-Field then a ...
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### Current sensitivity in transformer scheme with SQUID

I've tried to determine the maximum current sensitivity in this transformer scheme but I'm not sure if my solution is valid. I need to find the relation between the current in the input transformer ...
1 vote
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### Work done in a moving conducting bar and in a Faraday disk

I deeply apologize for my ignorance, but I am asking this since I still can't seem to grasp what my teachers relayed to me a few days ago about two exercises that I solved in an intrinsically wrong ...
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### Change in magnetic field due to induced EMF

I am currently experimenting with problems using induced EMF. I was dealing with a problem where I had a source of a constant magnetic field, but as I understand it when and EMF is induced it causes ...
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### Why is the EMF zero in a conducting rod perpendicular to length

Consider a rod moving in uniform magnetic field with its length perpendicular to the field. My textbook says EMF induced is zero in this case, but why won’t there be a transverse electric field across ...
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