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Back EMF in electromagnetic coil

I am trying to quantify the back EMF generated while actuating an electromagnetic coil, this would be included in a general calculation to estimate the coil output under a variety of conditions. My ...
Stefano's user avatar
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0 votes
1 answer
72 views

When a magnetic ball passes through a copper pipe vertically

Let's say a magnetic ball passes through a hollow pipe, which is a conductor (copper), vertically. We can observe that its acceleration is decreased when compared to a free gravitational fall. By ...
Rohit P L's user avatar
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2 answers
118 views

Can a magnet stop when falling through a copper tube? [closed]

It is known that when a magnet falls through a copper tube, it slows down according to the Lenz's Law. So theoretically if the magnet falls fast enough, can it completely stop for a moment? I have ...
dedmityay's user avatar
-2 votes
1 answer
53 views

Magnetic forces do no wok

The magnetic field is pointing upwards and uniform. Part C: Since the magnetic field does not do any work, the initial velocity of the bar should remain constant through time. But in the solution of ...
Akshat Shrivastava's user avatar
1 vote
1 answer
38 views

Bar Magnet Falling Through Metal Tube [duplicate]

I'm a bit unsure about the concept of a magnet being dropped through a conductive metal tube. I know that the change in flux will induce eddy currents in the walls of the tube which will resist the ...
Wilo's user avatar
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1 answer
66 views

Is there a magnetic force acting on a conducting ring falling due to gravity in presence of a uniform magnetic field that exists along $-z$ direction? [closed]

If so, then why? We know that a current carrying closed loop in a uniform magnetic field experiences no force but when it's suddenly pulled by an external force, according to Lenz law a magnetic force ...
Mr Mixo's user avatar
0 votes
0 answers
33 views

Does the net induced emf decrease in this case?

In a video from the YouTube channel veritasium about Misconceptions of electricity It is said that energy is mostly of the electric fields produced by the surface charges and battery , which make them ...
Razz's user avatar
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0 votes
2 answers
88 views

Is this a contradiction to Lenz's Law?

I've been really stumped on this particular concept. In Case A, when a bar magnet is brought towards a copper coil around a soft iron core, in accordance with Faraday's Law of Electromagnetic ...
Schrödinger's Cat's user avatar
6 votes
1 answer
518 views

If a loop is not complete, and magnetic field passing through it is changing; will their be emf induced in the loop?

In a setup like the one show in the figure: Will there be an induced EMF across the loop(given that the field is increasing)? (my dilemma is : since the loop is not complete, we cannot define the ...
Ash_Tag's user avatar
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1 answer
50 views

Faraday's Application on a Magnetic Dipole

Consider a closed loop wire with current flowing through it: Consider along the wire a battery $V$, a resistance $R$ and a capacitor $C$. We know the integral form of Faraday's law: $$\oint\limits_{\...
gluon's user avatar
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3 votes
2 answers
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Lenz's law, does magnetic flux as measured in Tesla decrease when current is induced?

Wikipedia defines Lenz's law as that the magnetic field created by the induced current opposes changes in the initial magnetic field, "Lenz's law states that the direction of the electric ...
BipedalJoe's user avatar
1 vote
1 answer
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Farmer stealing power from power line

In the situation above, we have a power line which uses an alternating current. This alternating current causes a change in magnetic flux through the loop below the power line, which induces a current ...
Stallmp's user avatar
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1 answer
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The effect of the inner diameter of a tube on the speed of a magnet falling through it

I have done the experiment of dropping permanent magnets through copper tubes and observing how they fall slower. With a tube that has an inner diameter close to the permanent magnet (a tight fit) the ...
Oongabu's user avatar
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3 votes
2 answers
261 views

How to explain different voltage and symmetry?

Imagine a magnet is falling along the axis of a uniform metal ring, there is an Eddy current in the ring due to changing magnetic flux and the direction of the current is determined by Lenz's law. ...
Ebi's user avatar
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0 votes
1 answer
139 views

Magnetic field produced by a changing current

When a current changes with time, it generates a changing magnetic field, according to Ampere's law. This changing magnetic field induces an electric field, according to Faraday's law of ...
Andreas Valadakis's user avatar
1 vote
0 answers
34 views

Levitation of a permanent magnet over a conducting surface

I have seen a method of magnetic levitation where a magnet moves over a conducting surface with its north pole facing downwards (or the conducting surface moves below the stationary magnet). At a fast ...
Oongabu's user avatar
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0 votes
1 answer
71 views

Understanding Electromagnetic Induction and Lenz's Law [closed]

I am having trouble understanding the concept of electromagnetic induction and its application, particularly in regards to Lenz's law. I am having trouble visualizing the relationship between the ...
mgcgian's user avatar
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5 votes
1 answer
487 views

Current through a solenoid: magnetic field gives a staircase graph

We were running current through a solenoid coil with an iron core, and measuring the resultant magnetic field strength. We expected a purely linear relation for the "current-field strength" ...
Valdemar's user avatar
0 votes
2 answers
170 views

Conservation of Energy with respect to Lenz's Law with moving coil

My knowledge of electromagnetism is quite elementary but I think I understand WPE and the Law of Conservation of Energy well enough. Here's what I understand of electromagnetic induction in a coil in ...
Kayen Jain's user avatar
0 votes
2 answers
156 views

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 ...
An_Elephant's user avatar
1 vote
2 answers
299 views

Regarding Lenz's Law presented in hyperphycsics

The following diagram is presented in hyperphysics as an introduction of Faraday's Law and Lenz's Law. If the red arrows represent the direction of current, then what do the positive and negative ...
I'm a lightbulb's user avatar
3 votes
2 answers
1k views

Why does a changing magnetic flux induce an EMF in "opposite direction"?

Faraday's Law of Induction tells us that a changing magnetic flux induces an EMF in the conductor, causing an electric current to flow. By Lenz's Law, we get the direction of induced EMF which turns ...
Shriesh Kumar's user avatar
0 votes
2 answers
476 views

Application of Lenz's law to ideal transformer: how is there a magnetic flux within the iron core?

In an ideal transformer such as the one depicted below (switch is open), a sinusoidally changing magnetic field will be created by the primary coil. However, according to Lenz's law, this sinusoidally ...
Piksiki's user avatar
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0 votes
1 answer
166 views

Does the direction of the change in magnetic flux matter in Lenz's law?

Does the direction of the change in magnetic flux matter ? For instance, here, the change in flux(taking downwards to be positive) is positive if the magnetic is falling with its north-pole facing ...
math and physics forever's user avatar
2 votes
4 answers
2k views

Does the direction of coil winding impact the direction of induced voltage?

In Case 1) and Case 2) (see the image below) induced current is flowing counterclockwise (from the magnet's POV) if we move the magnet towards the coil (and the circuit is closed, obviously). However ...
gvg's user avatar
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1 vote
1 answer
214 views

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?
Dawn Laing's user avatar
0 votes
0 answers
119 views

Does the magnitude of the induced current change?

The coil is circular and is closed, meaning that current can flow through it. So this enters a region of magnetic field where with time, more and more magnetic field lines cross it. My question is, ...
Blue Green's user avatar
0 votes
1 answer
429 views

Induced e.m.f and the speed of the magnet. (A-Levels Physics)

When a magnet is moved into a coil of $50$ turns at $0.12$ m/s, an E.M.F. of $3.60$ V is generated into the coil. What will be the E.M.F. generated when the magnet is removed from the coil at $0.48$ m/...
godai yuusuke's user avatar
-2 votes
2 answers
145 views

Are eddy currents produced by a coil of copper wire? [closed]

if I were too drop a magnet down a length of coiled copper wire would the motion of the magnet be opposed by eddy currents?
naman1008's user avatar
1 vote
2 answers
386 views

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 ...
unabdriged's user avatar
0 votes
2 answers
1k views

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 ...
user avatar
2 votes
1 answer
179 views

No emf generated on a loop lying outside changing $\vec B$ (but $\vec E ≠ 0$)

If we establish a changing magnetic field in a region of space, circular electric field lines are induced. This electric field extends even after we exit the region of the magnetic field. If a closed ...
Dodo's user avatar
  • 629
0 votes
1 answer
49 views

Induction due to solenoid

The electrical energy produce inside the coil due to changing magnetic flux on a coil . The mechanical energy of magnet or coil get converted into electrical energy(law of conservation of energy) . ...
Vaibhav Tiwari's user avatar
2 votes
4 answers
664 views

Question on Lenz law [duplicate]

According to Lenz's law , the direction of current induced in a coil is such that it opposes the very cause which produce it Why is this so?
Vaibhav Tiwari's user avatar
0 votes
2 answers
110 views

A question relating to Lenz's law

I was watching a Youtube video about magnetic induction and a guy explained to me that when a magnet moves by a piece of copper it causes a magnetic field in the copper which slows the magnet down but ...
no name the astronaut's user avatar
2 votes
1 answer
38 views

Weight of Diamagnetic Objects in Lenz Effect

I've seen the simple experiment of dropping a neodymium sphere down through a copper or aluminum tube where it falls at less than g. The "Lenz Effect" My question is: Has there ever been an ...
ClancyJohn's user avatar
4 votes
1 answer
1k views

Is diamagnetism really related to lenz's law?

I've visited multiple resources and read a lot of questions here on the nature of diamagnetism. I still don't understand if it truly has anything to do with lenz's law. In Walter Lewin's ...
EM_1's user avatar
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0 votes
1 answer
57 views

What is the influence of size of conductor on a repulsive force produced by a changing magnetic flux,according to Lenz's law?

On Lenz's law, Wikipedia says: Faraday's law states that the EMF is also given by the rate of change of the magnetic flux where epsilon is the electromotive force (EMF) and $\phi_B$ is the magnetic ...
Oliver Walters's user avatar
7 votes
1 answer
531 views

Is Back EMF produced in household wires?

Since we use AC for domestic purpose, shouldn't Back EMF (Counter-EMF) be produced in household wires? If yes, then the output voltage in the appliances will be less (that's what my stupid brain says! ...
Aghila C C's user avatar
0 votes
1 answer
118 views

What provides energy in mutual inductance to unconnected coil

In this mutual inductance setup: when current is passed through coil 1 the flux through coil 2 changes for a short amount of time which induces a current in coil 2 the direction of which, in ...
utkarsh's user avatar
  • 105
2 votes
3 answers
382 views

How to determine direction of current in this two loop system?

Let's say, there are two loops made from a single wire , loop 1 of bigger area and loop 2 having smaller area. Now let us suppose, a magnetic field exists in space perpendicular to the plane of the ...
Yash Agrawal's user avatar
0 votes
1 answer
93 views

Problem with magnetic flux

we know that an open surface integral of magnetic field bounded by a closed contour gives the magnetic flux. And rate of change of the magnetic field gives the Electromotive force. Now, if we have a ...
ozgun can's user avatar
1 vote
2 answers
987 views

How can we derive the polarity of the induced voltage in an inductor?

As we know, the voltage-current relation of a two-terminal constant-inductance inductor is: $v_L(t) = L \, \dfrac{\mathrm di_L(t)}{\mathrm dt} \tag 1$ I've managed to prove that equation without ...
alejnavab's user avatar
  • 344
0 votes
1 answer
113 views

What will be the result when we move a magnet aligned vertically towards a coil whose area vector is aligned horizontally?

According to Lenz's law, when we bring a magnet with one of its poles facing towards the area vector of a coil, an emf is induced in such a way that the pole is repelled. Im curious about what will ...
ThatOldWarlockMerlin's user avatar
0 votes
0 answers
157 views

How Lenz's law is based on conservation of energy?

To be honest, I understood Lenz's law. It doesn't violate conservation of energy. Kinetic energy gets coverted to electromotive force (EMF). But why? Like in case of upward thrown ball, kinetic ...
Nirvana's user avatar
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0 votes
1 answer
58 views

Electric and Magnetic Field [closed]

When an oscillatory current, I = Asin ωt is driven through the solenoid where A is the amplitude of the current, ω is the angular frequency and t is time, how do you find the expression for the ...
Phy07's user avatar
  • 5
0 votes
1 answer
156 views

Why is there no EMF induced or flux change of the left ring zero? [closed]

I tried by dividing the system into three parts, and flux is increasing for the left most and right most part and decreasing for middle, but am not able to arrange this in form of a battery, any help ...
Ritwik Shankar's user avatar
0 votes
1 answer
30 views

Lenz's Law for Moving Loops

This image above intrigued me since it shows different instances of Lenz's Law. I am learning about magnetic fields, but I get confused on the direction of induced magnetic fields. I was wondering ...
perseus's user avatar
0 votes
2 answers
2k views

Flux and emf induced graphs when magnet is dropped through a coil

I've been told that if you drop a magnet through a coil the induced emf and flux graphs would look like this: I understand that when the bar magnet is in the middle of the coil the emf induced is ...
notsoanonperson's user avatar
1 vote
1 answer
199 views

Faraday and Lenz's law

I'm trying to wrap my head around Faraday and Lenz's law. Mathematically it implies that $$\oint_{\partial s} (\vec E +\vec v \times \vec B) = \frac{d \phi}{dt}$$ where $$ \phi = \int \int \vec B \...
Orpheus's user avatar
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