All Questions
79
questions
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3
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80
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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 ...
0
votes
0
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39
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What is the induced electric field in a moving conducting material in a magnetic field?
I've been taught that the induced EMF in a conductor is the rate of change of flux in it, but Maxwell's equation
$$
\nabla\times\vec{E} = -\dfrac{\partial\vec{B}}{\partial t},
$$
only states so for ...
2
votes
1
answer
55
views
Does making a magnet move require more energy than a non-magnet?
I know that electric fields store energy, with their energy in an infinetesimal volume being proportional to $E^2$ at that point. I also know that a moving magnet creates an electric field (...
- 531
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1
answer
37
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Induced Electric field due to magnetic field in Faraday experiment
Regarding this experiment where a magnet is moved in and out of a coil -(see the picture)
what i considered to be true is that when there is a changing magnetic flux through the coil(due to changing ...
- 367
6
votes
4
answers
729
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How do Electric and magnetic fields generate each other (mathematically)?
Regarding electromagnetism, a changing magnetic flux$(\phi_B)$ produces emf by-$$EMF= -\frac{d \phi_B}{dt}\tag1$$
This emf creates a current which again creates a magnetic field given by-(bio-savart ...
- 367
0
votes
2
answers
36
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Inducing electric field vs Inducing magnetic field
Is it easier to induce an electric field using a changing magnetic field or the other way around?
The question is from my high school booklet, and I am pretty sure it was to be answered on an ...
- 15
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0
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27
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Does the Change in Area Not Affect EMF Calculation in a Time-Varying Magnetic Field?
I had this Question as a Homework :
Given a conducting frame of width $𝐿$. A mobile conductor is mounted on the knitting needle that moves on the closing one at speed $\vec{𝒗} = 𝑣\hat{x}$ while ...
- 101
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3
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110
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How current is induced when there is a change in external magnetic field?
If still charges in a wire loop do not respond to a(or have their own) magnetic field, then how is current is generated by changing a magnetic field? And why only a changing magnetic field? What ...
- 25
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1
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181
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Explaining Faraday's Law With Lorentz Transformations of $E$ and $B$ Fields
I've searched around for this but haven't come across a totally satisfying explanation yet. I'm trying to build a relatively simple model of how the Lorentz Transformations of the $E$ and $B$ fields ...
- 43
1
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0
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57
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Static toroidal magnetic field rotating inside toroidal winding
what would happen if I took a toroidal core, generated a static toroidal magnetic field in the core and then rotated the core around it's symmetry axis within a larger stationary toroidal winding ...
- 91
0
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1
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24
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Energy transmission from opposite magnetic field vectors. A wire with a current in a homogenous magnetic field
This is my first post and also the first time I've ever tried understanding a physics concept by approaching it with my own math logic so tips on trying to do this more effectively are also welcome
I’...
- 5
0
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0
answers
23
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Sources of Eddy current and hysteresis in linear materials
Following is an excerpt about transformer on load from Kothari and Nagrath, Electrical Machines.
The value of exciting current $i_0$ has to be such that the required MMF is established so as to ...
- 421
0
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0
answers
22
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How does proximity of a grounded conductor effect an electric / inductive field (and practical application)
My apologies - I'm missing a couple years of learning to be able to ask this question well, to know the right terminology.
Suppose a grounded conductor, such as a 12mm copper water pipe.
The grounded ...
0
votes
1
answer
97
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Conducting rod moving in magnetic field on a railing problem
We have a conducting rod (lenght $l$) moving with constant velocity $v$, on two symmetrical railings, and and everything is conducting. Rod has some resistivity $\rho$, while railings are purely ...
- 2,042
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2
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157
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Is the concept of motional EMF consistent with Faraday's Law?
Consider a circular homogeneous metallic coil sliding on a smooth horizontal surface in a region of uniform magnetic field $B$ which is perpendicular to the face of the coil. By Faraday's law, the net ...
- 341
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1
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47
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Can ionized air be used as a conductive medium for eddy brakes?
Sort of a conceptual engineering question, apologies if I am missing something, my background is in mechanical engr.
Essentially, I was inspired by the classic experiment of dropping a magnet in a ...
0
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2
answers
78
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What type of electric field is created by time varying magnetic field?
Example when an current carrying loop is placed in external magnetic field varying with time some emf is produced in the coil now we know that emf is due to electric field and the loop is experiencing ...
6
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3
answers
1k
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Suspicious EMF equation
Some context: I am trying to get the equation of motion for a dipole magnet falling through copper pipe. To proceed I need to calculate the EMF. We can do this by using Faraday's law,
$$\oint_{\...
0
votes
1
answer
292
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How to identify north pole of a magnet using only a battery, and a copper wire? [closed]
I have a magnet, a copper wire, and a battery. I need to find the north pole, and the south pole of a magnet using only these items. (not a compass).
Here's my attempt: create a circuit, battery is ...
0
votes
1
answer
257
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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 ...
- 4,170
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2
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84
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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?
- 480
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1
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233
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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,-...
- 105
1
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3
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512
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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 ...
0
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5
answers
512
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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}...
- 170
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1
answer
262
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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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2
answers
1k
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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
0
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2
answers
151
views
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 ...
- 13
0
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2
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591
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Doesn't Faraday's law violate conservation of energy?
Faraday's law says that if we have a changing magnetic field, there will also be an electric field (basically). I already know that both fields have energy. Is this energy given when accelerating the ...
- 857
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62
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Why moving magnet releases more Magnetic radiation as the number of charges near it are increased?
Why does a moving (at constant velocity) magnet release more energy in the form of magnetic fields when the number of charges placed near it are increased?
Say two current carrying coils $C1$ and $C2$ ...
1
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1
answer
286
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Can electromagnetic field(EMF) meter used to detect electromagnetic pulse(EMP)?
In theory,can electromagnetic field(EMF) meter used to detect electromagnetic pulse(EMP)?
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