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Questions tagged [induction]

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2answers
67 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 ...
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1answer
41 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
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1answer
20 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
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1answer
45 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?
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2answers
75 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
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0answers
42 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 ...
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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 ...
2
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2answers
118 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
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2answers
55 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. ...
27
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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?
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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
77 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
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1answer
43 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
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1answer
47 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
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1answer
40 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? ...
0
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2answers
55 views

How is it possible that the two voltmeters in parallel measure these different voltages

I'm currently studying induction law and circuits with inductors. I came however with the following circuit: Now my text says the following: "Unlike what your intuition might tell you, oscilloscopes ...
0
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2answers
54 views

Is induced EMF proportional to the square of the number of turns of a solenoid?

In order for this question to be clear I must first give some context: Consider a 10cm long solenoid (solenoid A) of radius approximately 1cm with 400 turns. Let the current in $A$, $I_A$, ...
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3answers
41 views

What happens when a super large charge is brought close to a conductor with limited supply of charges?

Imagine the following induction scenario: a super large charge +Q is brought close to a real conductor with limited supply of charges; that is, the total charge of all electrons inside this conductor ...
2
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3answers
220 views

Can Kirchhoff's Voltage Law be applied here?

First, consider a simple circuit comprising of an ideal battery of EMF: E and a single resistor of resistance R. Imagine that the switch is opened in the circuit. In the battery, some internal ...
1
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1answer
39 views

Faraday's law superconducting [duplicate]

When we say flux can't be changed through superconducting coil , because resistance is zero , So this implies there is no induced emf in the coil , If it is so what makes current flow in the coil ...
-1
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3answers
53 views

Self induced EMF in DC

Why is self induced emf much greater than the source voltage in a DC supply when the switch is opened?
0
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2answers
79 views

Difference between induced emf in a loop and a wire

In the given figure, I was asked to calculate induced emf in the loop and individual wires of the triangle. I have a doubt that when I am calculating the emf of the whole loop, between which two ...
4
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5answers
145 views

Inductor in A.C. Circuit

I am reading about inductors connected in A.C. Circuits. I understand mathematically that the current lags behind voltage. But what is the physical explanation for this? My understanding: As the emf ...
1
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1answer
94 views

Magnetic field inside conductor and linearity of eddy currents

Eddy currents are currents that are generated in a conductor to produce magnetic fields that oppose the magnetic field originally produced by current flowing in the conductor. The figure below (from ...
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1answer
62 views

Will a pulsating electron beam passing through a copper pipe induce eddy currents within the copper pipe?

If a pulsating electron beam is beamed down the center of a copper pipe, so as to not make any physical contact with the pipe, the beam should create a pulsating magnetic field that will not change in ...
0
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1answer
41 views

Electromagnetic induction and magnetic field (conducting rail problem)

Since we know the work done by a magnetic field is zero.now how does the magnetic field changes the kinetic energy of rod when it applies force BIL (where I is current at any instant) moreover if we ...
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3answers
184 views

Self Induction and Inductance [closed]

A coil with zero resistance has its ends labeled a and b. The potential at a is higher than at b. Which of the following could be consistent with this situation? Mark all that apply a. The current ...
0
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1answer
45 views

Can I induce AC current with a straight piece of wire and a spinning magnet?

The idea is, I have a fast spinning magnet and next to it a wire (with 2 free ends). When the + pole is next to the wire it will attract the electrons, and when the - pole is by the wire it will ...
2
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4answers
146 views

Is electromagnetic induction a result of the Hall effect?

I know that an EMF is induced when there's a change in magnetic flux through a conducting surface. Is this due to the Hall effect? By this I mean, do the delocalised electrons in the conductor ...
0
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1answer
46 views

Energy conservation in induction

Let's say we have 2 inductively coupled circuits with mutual inductance M, and Circuit 1 ist connected to a power source, changing its current by $\frac{dI_1}{dt}$, then the potential induced in ...
1
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1answer
30 views

Effect of greater coils on induced current in a solenoid

Simple case:- A bar magnet is inserted into a solenoid with 'n' turns at velocity 'v'. The current is measured using an ammeter that is part of the complete circuit of the solenoid. My question is ...
2
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1answer
110 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 ...
0
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0answers
69 views

Induced EMF problem (rotating conductor loop)

I have a question in my book and it’s confusing me a bit. I tried to search online for similar solved problems but couldn’t succeed. So here it goes: Calculate the induced EMF in a conductor loop ...
0
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2answers
41 views

When a charged rod is brought close to a conducting metal of any shape, is the magnitude of charge induced on the metal same as that of on the rod?

I think the question title is clear. What happens when other conducting metals are also around the rod? How could you explain intuitively?
0
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2answers
156 views

Statement of Lenz's law

In Lenz's law we state that direction of the induced current is such that it opposes the cause that produces it. But can we state the direction of induced emf instead of current? If by direction ...
2
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1answer
45 views

Will salt water spin if put in place of rotor in induction motor?

If I have a bottle of salt water and put it in place of rotor in induction motor, will the salt water spin ? Why / why not ?
1
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1answer
47 views

Comments on the Magnitude of Induced Charge

Is it necessary that the induced charge be always less than or equal to the inducing charge? Why can't it be greater? Could someone please explain why this happens, and to what extent can we comment ...
0
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1answer
45 views

Finding induced magnetic field strength given current.

I'm working on a project involving a Tesla Coil, and I was hoping to figure out how strong an induced magnetic field would be with an input voltage of X. Is there an equation to help solve this? I'm ...
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5answers
223 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
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2answers
457 views

Self Induction: Why does light bulb flash when circuit switched off and not when switched on?

When the switch is closed the current through the coil changes and hence so does the magnetic flux around the coil. This induces an emf in the coil which, in accordance with Lenz's law, will oppose ...
0
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1answer
40 views

What would happen if i move a rectangle shaped conductor in a magnetic field?

I know that in situation II there will be a induction current; and there will be no induction current because of the constant magnetic flux in situation I; but when we move a linear conductor in a ...
0
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2answers
71 views

Inductors in a.c. circuit problem

As written in my book and as I saw on some videos about inductors that in an ac circuit if an inductor is connected with an a.c. source then the induced emf would be the same voltage as the source ...
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0answers
84 views

Vector calculus and principle of reciprocity MRI

I'm studying the principle of reciprocity for the MRI. At some point during a calculation the book states that: $$\oint d\vec{l} \cdot \left[\int d^3r' \frac{\vec{\nabla'}\times\vec{M}(\vec{r}')}{\...
1
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1answer
367 views

Do transformer follow Ohm's Law?

We khow that due to Ohm's Law, $I$ is proportional to $V$ So if $V$ rises, $I$ should rise too. But in a transformer when $V$ rises, $I$ lessens. Why does this happen? It seems like transformers ...
2
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0answers
198 views

What is the physics behind the vibrating feeling you get when you touched an inducted metal surface?

When I was last working on the highway, I stopped to help a motorist parked under high tension power lines. I'm driving a large Ford Transit van, fairly box shaped. My van was parked 90 degrees (...
0
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1answer
137 views

Why does a Crookes tube work when connected to an induction coil?

From reading the answer below (regarding the mechanics of an induction coil) and the wikipedia article, it is clear that induction coils produce AC. However, the following excerpt from the "Crookes ...
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0answers
149 views

Some question about quantization of LC -Circuit and transmission line resonator

In this post @DanielSank left a good answer about Lagrangian method for an LC-Circuit. But for me is not clear the next things: When he wrote the equation for current and voltage according ...
0
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1answer
70 views

the conservation of the Electric displacement vector

Good day everyone! Consider that we have the following capacitor ( look at the image bellow) that is partially filled with 2 dielectrics with a relative electric constant of er1 and er2, and we have ...
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1answer
812 views

induced charges inside a capacitor with two dielectrics

consider that we have two dielectrics inside a capacitor as shown in the picture, let0s consider also that Q is the charge of the capacitor and d the distance between the two plates , the first ...
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0answers
47 views

What is the range of the validity of the Maxwell-Faraday equation?

Similar to the question about the range of the validity of Coulomb's law, I am looking for references to literature that investigates the emirical bounds of the Maxwell-Faraday equation. However, it ...