Questions tagged [induction]

The tag has no usage guidance.

0
votes
2answers
514 views

Why can't mutual inductance create perpetual electricity?

Consider the following image. When the battery is connected then current starts flowing through the primary cicuit and magnetic flux changes through the coil, this causes electricity to be induced in ...
0
votes
1answer
54 views

What does direction of EMF mean?

In faraday's law it mention's direction of EMF( like in closed loopit is clockwise or anticlockwise depending on direction of motion of magnet) but defination of EMF is roughly Potential diffrence ...
3
votes
2answers
197 views

Can induction coils heat air?

I understand that induction coils can heat up conductive materials such as metals, but I'm wondering if they can heat up normal air. And if they cannot, can ionizing the air beforehand allow it to be ...
0
votes
2answers
239 views

how is motional EMF developed?

According to my textbook and several other sources on the internet if we we move a rod in the direction perpendicular to a uniform magnetic field, the electrons will also move as per the direction ...
1
vote
1answer
41 views

How to calculate induced emf of moving rod?

I have the following exercise: A copper rod with length L is moving on two frictionless conducting rails, in a distance a from an very long straight conductor. The rods resistance: R. Ignore any self ...
0
votes
1answer
230 views

Does displacement current occur in an inductor?

We have learned in school that displacement current comes about due to a change in electric field flux per time in a capacitor (Ampere-Maxwell Law). Does the same displacement current come about in an ...
1
vote
1answer
119 views

What would happen if a magnet was pushed towards a copper tube in space?

So the question was inspired by one of curious comments on youtube. What exactly would happen if you pushed a strong neodymium magnet towards the copper tube (aiming for the opening in an effort to ...
0
votes
1answer
167 views

currents in an isolated metal exposed to an alternating uniform electric field

For example, let's look at a metal sphere between a capacitor's (infinite) plates. Let's run an AC current through the capacitor, resulting in an oscillating electric field. The charges will move in ...
2
votes
2answers
34 views

Is it possible to use Ampere's law to calculate vector B around short straight line conductor?

Maybe this question sounds easy, but I would really be grateful if someone could give me an explanation if it's true or not. I'm not sure if I understand it good enough.
3
votes
2answers
274 views

Why induction coupled plasma use RF frequencies?

The frequency I see all the time is 13.56mhz,I understand that when you want to make heat treatment surface finish on steel,you use high frequency in the heating coil so the skin effect heats only the ...
0
votes
2answers
383 views

Why will a magnetic field cause a ring to hover?

I was attempting a homework question which went like this: Where the crosses indicate a magnetic field in that rectangular region pointed into the screen, and we're asked which of the rings would ...
0
votes
0answers
33 views

Violation of conservation of energy (seemingly) in process of electromagnetic induction

A bit long question but it's really bugging me a lot. Say we have a closed circular conducting loop at rest and initially a bar magnet rests along its axis with north side facing the loop. Now we ...
0
votes
2answers
29 views

Only getting positive values for induced voltage? [closed]

We have to draw a voltage over time graph for the induced voltage in a coil for 2 whole turns. $N = 10$ $B = 30mT$ $A = 100cm^2$ The coil is rotating at 20Hz We have the formula: $2πNBAfsin(2πfT)$ ...
0
votes
1answer
312 views

How eddy currents effect the impedance of source?

When we connect a bigger resistance to a transformer, the current decreases both in the primary and secondary. To be able to maintain the same current, we'd have to increase the voltage. Now imagine ...
2
votes
0answers
23 views

Finding the voltage across an inductor when opening the switch [closed]

Well, I've the following circuit: In the circuit I want to find the voltage $\text{V}_{\text{Y}_1}\left(t\right)$ as a function of time, after I open the switch (this switch was closed 'forever' ...
1
vote
1answer
472 views

Measurement of electrostatic induction

How is it with the electrostatic induction measurement? Everywhere you can read about the effect of electrostatic induction but I still can't found any detailed explanations or quantitative ...
0
votes
1answer
446 views

Point charge inside a electrically neutral cavity in conductor placed eccentrically, and effect of external electric field if switched on

bear with me, but i would like a definite answer, now, starting off the external charge density on the outer surface of sphere WILL be uniform by unique solution of Laplace equation and letting the ...
0
votes
0answers
56 views

What is the QM equivalent of induction?

And regarding electron correlations, reciprocally what QM ones are strictly due to classical induction and near field effects? Edit: thanks to whoever thinks necessary to downvote questions without ...
4
votes
2answers
11k views

Transformer and magnetic field/flux through the iron core?

I am familiar with how a transformer works. This is the diagram that I found on the wikipedia page: The current through the red solenoid varies with time, which creates a time-dependent magnetic ...
2
votes
0answers
2k views

Ed Leedskalnin's “Perpetual Motion Holder” (PMH)

Edward Leedskalnin (Coral Castle) describes a perpetual motion holder in his writings. I've built one and pretty much know how it works (I think). It is NOT a perpetual motion device by any means, ...
0
votes
0answers
27 views

Transformer Equation Confusion

I have read some posts on here which I think to revolve around my problem too but couldn't really understand the explanations. So basically, I have seen how the Transformer equation is derived: $\...
3
votes
2answers
129 views

Relativistic Induced Magnetic Field in particle's frame

Suppose there is a constant magnetic field: $\vec{\mathbf{B}} = B \hat{z}$. A charged particle orbits that magnetic field perpendicular to the magnetic field, and induces a magnetic field in the ...
1
vote
1answer
522 views

Torque on a charged ring

I have been studying electromagnetic induction. As I understand, a magnetic field will exert a force on a moving charge. What I would like to know is whether a changing magnetic field will exert a ...
0
votes
1answer
46 views

Infinite Electricity from Photon Inside Closed Box with Magnet Attached in a Coil? (Thought-experiment)

Let's say I have a very large box with a magnet attached to the outside. Inside the box there is a perfect mirror on each side. I open my box and quickly shoot in one photon before shutting it. After ...
0
votes
1answer
278 views

Finding the induced current in a loop and force acting on the conductor

The conductor has a velocity to the right and is part of a closed loop (see the picture). Find the direction of the induced current and the direction of the magnetic force on the conductor There must ...
2
votes
1answer
147 views

Do magnets attract magnetic materials by inducing magnetism in them?

Here are 2 concise excerpts from a book I have been reading:- 1.A permanent magnet produces its own magnetic field. An induced magnet is a material that becomes a magnet when it is placed in a ...
3
votes
1answer
65 views

Can $F=qvB$ be applied to a solenoid and a parallel moving magnet?

If you take a scenario like this, Charge gathers at either end, and if you could somehow form a complete circuit without there being a canceling effect, there would be a current flowing. This makes ...
0
votes
0answers
30 views

What is the difference between Charge By Induction using two conductors, two insulators, and one conductor + one insulator?

I know that when you're charging by induction, it doesn't require two objects to contact for that to happen. Let's say you have two Van de Graaff generators that are initially at neutral charge. Let's ...
0
votes
0answers
22 views

Motional EMF with a rod in a closed loop

Let me preface this by saying that while this is a problem which came from my college physics class, it was not a graded assignment, it was optional study material (and you can see from the photo I've ...
0
votes
1answer
124 views

the nature of the electromagnetic induction

the electromagnetic induction: is it a magnetic force (Lorentz Force) or an electric force generated by the temporal variation of the magnetic field (Faraday's law)?
1
vote
5answers
286 views

What does inductance mean?

I have the following notion of inductance. When a current flows through a conductor a magnetic field is set up. Depending on the shape of the conductor we get a magnetic flux through the conductor. ...
0
votes
2answers
127 views

Induction heating

An induction cooktop has a high frequency power source that is applied to a coil. I was wondering if you could take the high frequency electronics on a cooktop and instead of a coil take a 30 or 90 ...
1
vote
3answers
313 views

What happens if I have a square conducting wire being permeated by a magnetic field and the field suddenly disappears?

Suppose there is a square conducting wire in a magnetic field. The two vertical branches will have the same emf, and the two horizontal branches will have 0 emf, resulting in a net emf of zero and ...
3
votes
2answers
68 views

Could magnetic fields really be completely substituted by relativity and electric fields?

In many textbooks (especially those for undergraduate level), magnetic fields are described merely as a relativistic side product of electric fields when considering frames in motion relative to ...
1
vote
1answer
112 views

Simple question regarding electrostatics (charged glass rod to oil and water)

How come a steady stream of oil got repelled by a positively charged glass rod, whereas if water were used instead, it became attracted to the rod all of a sudden? Is it because water is inherently ...
0
votes
1answer
31 views

Current induced by permanent magnet moving along toroid coil

(It's not really shown in the pictures, but please assume that the coils are included in a closed circuit in both configurations. Maybe they could serve as a tension source in their respective circuit ...
1
vote
1answer
51 views

Self-induction and conservation of energy [closed]

back EMF when switch is open is greater than back EMF when it is on; is that opposes the law of conservation of energy?
8
votes
2answers
3k views

Magnetic Levitation : Confusion with Lenz's Law

Considering the above diagram, I am failing to see why the aluminium ring floats upwards rather than oscillates. I understand Faraday's law, but I am struggling with Lenz's law - as there is an ...
1
vote
2answers
83 views

Scientific reason behind electromagnetic induction [duplicate]

What actually happens inside a loop when placed in a changing magnetic field that EMF gets induced across it? And also if it is connected and the direction of the magnetic field is changed then ...
0
votes
2answers
34 views

Induction coil varies voltage

I was recently given this question by a friend as part of her homework: The gist of the question is: Say I have a laboratory induction coil with a primary coil which I can slide in and out of the ...
0
votes
0answers
44 views

EM Induction in non-uniformly conducting ohmic toroid, thought experiment

Assume that there's a conducting toroid with radius of revolution $R$ and an own radius of $D$ so that the cross section of the toroid is given by $\pi D^2$ Assume that there's a circular region of ...
2
votes
2answers
124 views

Now what will happen in this circuit?

Consider a circuit as shown in this figure below- Assuming switch S1 is closed such that current flows in loop ABCDE for a long time and steady state is reached. Now, my question is simple, suppose (...
0
votes
2answers
95 views

Why is the integration constant in a purely inductive AC circuit assumed to be zero?

While studying about AC circuits, I came across the usual differential equation of an AC circuit (in which the voltage across the source is a sinusoidal function of time) containing an inductor only. ...
0
votes
1answer
310 views

How do Eddy currents follow conservation of energy?

When wind blows, leaves of a tree move and they gain kinetic energy. In this case air molecules loose kinetic energy and transfer it to the leaf. But In case of eddy currents moving inside a conductor,...
27
votes
2answers
4k views

Please help identify this physics apparatus!

This was my grandfather’s and have no idea what it is only that it is some piece of physics equipment! The main black cylinder doesn’t seem like it wants to rotate but not sure if it should?
1
vote
0answers
14 views

How to calculate the limits for volume and mass for induction heating samples?

I'm evaluating the feasibility of using volumetric induction heating to quickly heat up steel molds. One thing I have come across is that induction heating really only works for surface heating or for ...
3
votes
1answer
98 views

Is there is any way to prove the Faraday's law of induction?

I want to know if there is any way to prove the Faraday's law or is it just an experimental observed phenomena? More specifically, is there any reason why the proportionality constant is 1? How did ...
0
votes
1answer
44 views

Is Faraday's induction principle applicable in outer space?

Is it possible for an AC generator to actually generate electricity let's say being in a ship orbiting Mars or on the surface of the moon? Does Faraday's principle require the magnetig field of the ...
1
vote
1answer
69 views

Faraday's law intuition

I am trying to understand Faradays law of Induction. As far as I know when we are speaking about the E field we mean the field caused by charges(stationary or moving) whose value we can calculate by ...
2
votes
1answer
41 views

Electromagnetism— why do we only care about flux inside the loop? In other words, why is the area in 'φ=AB' the area bounded by the loop?

When we calculate the emf induced by placing a loop of wire inside a changing magnetic field, why do we use the area bounded by the loop to calculate total flux and then the rate at which it changes? ...