Questions tagged [electromagnetic-induction]

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Analytical expression for the EMF induced in a solenoid due to motion of a permanent magnet

A permanent magnet (cylindrical) of length (l) and radius(r) with velocity v(t) along z-axis as shown in the figure. I am looking for analytical expression for the induced emf in a coil with N turns, ...
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Need Help with Proving Faraday's Law of Electromagnetic Induction with Experiment Results [on hold]

I have recently conducted an experiment measuring emf over time and magnetic field strength over time as a bar magnet fell through a coil. The magnetic field was measured by pointing a magnetometer to ...
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Drone's sufficient engine RPMs initiated by Magnetic Fields

I've seen many videos where magnets are used to initiate and boost RPMs. Most of them are fake, where people are using compressed air at the backstage. Did anyone of you actually tried to challenge ...
40 views

Nature of induced magnetic field lines in cylindrical capacitor

What is nature of the induced magnetic field lines inside a cylindrical capacitor which has a time variant potential gradient across it? For a parallel plate capacitor, its straightforward: the ...
33 views

On a rotating body is induced emf dependent on reference frame?

The magnetic field K is pointing inwards. Why does the induced emf differ between points B and D if the frame of reference is changed from B to A?
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Why can't a current carrying loop (curl of the electric field exists) produce a time varying magnetic field?

If a time varying magnetic field can give value to the curl of an electric field, why not the other way round? That is, why can't an enclosed loop with some emf produced (basically a current carrying ...
21 views

What is the effect of charge of Sun induced on the Earth as compared to gravity?

As we know gravity is a less attractive force than the for of electric and magnetic fields. My question is where does the effect of magnetic field go while gravity has pull on earth. At this point ...
45 views

Is this video about electrical transformers correct?

In this Youtube video, at around 5:10, it shows two graphs, when we have constant increase in voltage on the left, we have constant voltage on the right, but then when voltage stops changing on the ...
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Trouble understanding fractional flux linkage

My question is quite similar to one in the link: Flux linkage inside of a conductor. But I have trouble understanding any of the answers provided there. Specifically my question is the following: I ...
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If a metal rod of length l is moved perpendicularly, in a straight line, inside a uniform magnetic field, will a emf be induced in the rod?

The magnetic flux density is constant, and the rod is being moved inside the field. And if an emf is induced, how does the flux linkage change in this rod? The cross sectional area of this rod ...
8 views

Helmholtz coil construction and working

If I connect Helmholtz coil to ac( 220v, 50HZ) mains then is it means that the field it will generate is alternating field? Then how it generates a uniform magnetic field?
27 views

A travelling field; Feynman lectures on Physics Volume 2

In Feynman's Lectures on Physics, volume 2, Chapter 18 (18-5), we look at the creation of a electromagnetic field, due to a moving infinite sheet of charge, By looking at the Maxwell equations ...
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Inductors in Transformers

Why is it the flux change which induces the ac current of primary coil equal to the flux change that primary coil induces on the secondary coil? Is it possible to prove this? slide from video ...
12 views

Is magnetic flux depending on the orientation of ferromagnetic rotor?

I have attached a picture of Reluctance motor setup. When I turn on the AC source, Magnetic flux lines will build up. My question is, will the magnetic flux will be a function of the angle turned by ...
47 views

Time varying magnetic field and induced electric field

Well I would like to start with asking few questions for you to provide a detailed solution and whose details has been clearly mentioned in the above image. It would be helpful if you could clearly ...
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Induced Electric Field due to Infintely spread out, changing magnetic field

If I have a uniform, downward pointing magnetic field which is spread across a very large region and the magnitude of the magnetic field is increasing with time, what is the shape of the induced ...
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Force on a stationary negatively charged conductor in a changing field

If a magnet is brought near a conductor it induces a current in it caused by the movement of free electrons which behave like tiny magnets. But if a magnet exerts a force of attraction on the ...
54 views

Moving iron rod through solenoid [closed]

What effect(s) does a moving iron rod have on a solenoid? Which of the graphs is correct?
8 views

Correlation between the radius of a cylindrical coil with the curl of the electric field induced in that coil

A background of the lab, I am currently working on: I have different sizes of cylindrical coil of wire, each with different radius. I then pass the coil through a near uniform magnetic field and then ...
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Finding direction of induced EMF

How should I find out the direction of the EMF induced in a rod of any length $l$ rotating with an angular speed $w$ in a region of magnetic field (perpendicular to the plane of the rotating rod) ...
25 views

Why the electric field induced in the $\phi$ component, non-zero as compared to the $s$ and $z$ which are zero?

If we take a coil in a uniform magnetic field, move it around to induced some emf around the coil. And so in order to calculate the curl of the electric field induced in cylindrical coordinate system, ...
70 views

Explanation of motional EMF in a rod

Why does an EMF generate across a rod moving linearly in a region of magnetic field constant with space and time? While proving it, we considered the rod to be connected to a conducting rectangular ...
96 views

Explanation of rotational EMF

Why does an EMF $\frac{1}{2}B\omega R^2$ get created across the radius $R$ of a Faraday's disc when it rotates, with angular velocity $\omega$, in a magnetic field constant with both space and time? ...
25 views

Magnet oscillation with coils

I am trying to conduct an experiment in which I will try to find the natural frequency of a cantilever. To oscillate the cantilever, I thought I could use a magnet and a current-carrying coil wire ...
28 views

Electric Field in conductor near Solenoid

My question is essentially a follow up to this question. It's answer says, the mobile charges in the conductor distribute themselves to make E = 0 inside the conductor. But, I don't understand how a ...
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Question about induced current with an axis parallel to magnetic field

I am currently going over a physics test. One of the questions asked if a square loop of wire perpendicular to a uniform magnetic field entering the page has an induced charge if it is spun ...
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Experiment: Magnet falling in a copper/aluminum pipe

We know that when we release a magnet in conducting pipe (aluminum, copper, etc..) it will be subjected to a magnetic force induced by the induced current. This magnetic field will be created in a ...
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Calculation of eddy currents and subsequent heating in a metal, ATEX-rated junction box

We are building a system which will make use of a stainless steel junction box to connect different circuits within it. This will be located in a hazardous offshore environment so we will be using an ...
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Why does inductor current lag the applied voltage at its terminal by 90 degrees?

I studied electromagnetism and I am currently working with Inductors. I could not figure out the physical reason based on electromagnetics on why inductor current lags the applied voltage by 90 ...
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Magnet moving between $2$ separate coils, connected to a circuit

I was thinking about a question regarding a magnet entering a coil when the following thought came: what if we unravelled the middle of the coil such that it splits into $2$ equal parts, and connected ...
143 views

Current in only inductive AC circuit

Current through a LR circuit is given by $$i=i_0 (1-e^{\frac{-tR}{L}})..1$$From here I can observe that as I tend R towards 0 no current flows through the circuit , and current will be 0 when the ...
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What is actually being removed when a metal conductor is grounded?

I found this image earlier this morning, and yes, there are a lot of diagrams/illustrations about this, transferring charges by induction has been introduced since the very beginning of high school ...
Does grounding set the potential on a surface of a sphere to $~0~$ or the potential due to the charges of the sphere to $~0~$?
I'm understand that grounding sets the potential to $0$, but I'm confused as to which potential it sets to $0$. Let me explain my question: If I have a sphere and I bring a positive charge near it, a ...