# All Questions

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161 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 ...
46 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 ...
196 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 ...
469 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 ...
83 views

### Why would a steel tube vibrate under high voltage?

Can anyone explain why a vertical steel tube, standing with one end in contact with the ground under a $230 \space kV$ electric transmission tower, would physically vibrate at high frequency? I'm not ...
527 views

### Straight wire with constant electric current and square loop in the gravity field

I was trying to solve this exercise but I found some difficulties in the proposed solution... The text is: A square loop of wire (side $l$, mass $m$, resistance $R$) lies on the $xz$ plane, below a ...
941 views

### Current induced in loop moving out of magnetic field : contradiction using Fleming's right hand rule

In the picture shown magnetic field exists into the plane (denotes by the X) and the loop (iii) is moving out of the region of the magnetic field. According to Lenz's law, the induced current will ...
1k views

### What happens when an inductor is charging from a battery?

I asked a similar question here some time ago, however I feel that this question is different and was not answered in the previous post, although it certainly is related. My question here is, what ...
50 views

### Current Induction Explanation

Using $$F_\text{magnetic} = (BIL)_\text{wire} = (BQv)_\text{particle}$$ we can say $F\propto v$ as $B$ and $Q$ are presumably constant. Is the magnetic force proportional the radius, or distance, ...
1k views

### Magnetization and Demagnetization of an Inductor

when we apply the AC voltage to an Inductor the Average power over a complete cycle is zero. the figure in my book explains it. but I couldn't understand it, I could have directly asked the question ...
250 views

### Does terminal voltage decrease as we draw current?

If the secondary is an open circuit or the current taken from it is small, then to a good approximation $ε_s = v_s$ where $ε_s$ and $v_s$ are secondary voltage(induced) and secondary terminal ...
58 views

### If a purely inductive circuit is started in presence of gravity, will the power source ever run out? [closed]

I have read that purely inductive circuits do no work. So if an Inductor with an AC source, coming from an inverter is set up, will the source of power ever run out due to work against gravity? This ...
51 views

### How is it possible to even develop any current in an inductor?

Potential difference across an inductor (ie p.d. between current exit point and current entry point) is given as $$V= -L\frac{di}{dt} -iR,$$ where $L$ is the inductance of inductor and $R$ is its ...
1k views

### Does voltage always cause current?

I'm wondering if the following statement is fully correct: Voltage causes current through a closed circuit, but through an inductor it is the change in current that causes a voltage. Obviously ...
3k views

### Self induction in a circular coil

There's a formula for self inductance : $$L=\frac{n\Phi}{i}$$ where n is the number of loops. But the book also says self inductance is directly proportional to $n^2$ I totally agree with the ...
7k views

### How to find the direction of an eddy current?

Suppose there is a magnetic field going from left to right. Suppose a thin sheet of metal conductor (e.g. a 1m*1m square) is dropped through the magnetic field such that the plane of the conductor is ...
590 views

### Eddy Currents – Tubes with slits

When a magnet falls down a tube, eddy currents form and flow around the tube, perpendicular to the direction in which the magnet falls. However, when there is a vertical slit in the tube, are either ...
322 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 ...
1k views

### The image current due to moving charges and a current carrying thin wire

Suppose we have a plane conductor and a stream of positively charged particles of mass m moving parallel to the plane conductor at a distance $d$. The trajectory can be assumed to be straight. An ...
131 views

### Magnetic field and electric field induce one another forever [duplicate]

A changing electric field produces magnetic field and vice versa. Does that mean that this process will carry on forever? Think of a circuit with a capacitor. The magnetic field due to the current at ...
1k views

### Induced electric field due to a moving wire

An infinite wire carrying a constant current $I$ in the $\hat{z}$ direction is moving in the $$y$$ direction at a constant speed $v$. Find the electric field, in the quasistatic approximation, at the ...
1k views

### Currents induced by rotation of a coil about magnetic field lines

If the coil on the left is rotated about the magnetic field lines, will there be an induced current? I know that the flux concerns only the component of the magnetic field perpendicular to the plane ...
658 views

### Force on a loop with induced current

Consider an infinitely long ideal solenoid with current $I$, radius $a$, turns per unit length $n$. Put a closed conducting loop around it (radius $b > a$), on a common axis through their centers. ...
435 views

### Does the skin effect and the proximity effect cancel each other out?

I'm interested in how the Skin Effect and the Proximity Effect interact with each other. From what I can understand: The Skin Effect is when AC current 'collects' on the skin of conductors due to ...
55 views

### Cooling induction current generation

We know that conducting materials can be heated by electromagnetic induction. Is it possible to generate current using a cooling process?
345 views

So we know that the EMF is induced by change of flux. The thing that was always confusing me is the following: we start changing the magnetic field which in turn induces electric field which makes ...
707 views

### Can the potential difference produced in Van De Graff generator used to generate electric current?

If this machine can build up high voltages of the order of millions of volts, can we use this voltage to generate a current of electrons? The building up of potential difference can result in an ...
689 views

### Faraday's law and “infinite induction”

I may have confused after thinking too much about Faraday's law. If an emf is induced in a circuit due to some changing magnetic field, the induced current will be in a direction such that the "...
204 views

### Back EMF & Current, how can we make the current $I$ stable?

Let's assume that we have a wire with $10 \, \mathrm{V}$ across it and $1 \, \mathrm{A}$ flowing through it. Then if this conductor is introduced to a changing magnetic field, inducing $-EMF$, can we ...
1k views

### Induced current and Ohm's law

I am trying to explain this problem: A circular conducting loop composed of N turns of wire has a radius of r and a total resistance of R. Perpendicular to the plane of the loop is a magnetic ...
1k views

### Is it possible to use induction ampermeter to measure power consumption of electric water heater and dryer?

I hope this practical question is not OT and not too trivial for this forum. I am renting an apartment in a duplex with a shared water heater and dryer. Turns out, both water heater and the dryer are ...
56 views

### Would a $50\: \mathrm{Hz}$ spinning magnetic plate in front of a human generate harmful current?

We know that spinning magnetic plate will generate current inside any wire. so if we stand before 50Hz spinning magnetic plate, then, does that 50Hz spinning magnetic plate in front of us (human body )...
92 views

### Eddy Currents in Metal Implants

Related: Why is stainless steel a poor conductor of electricity? I recently had a metal implant, and I'm psyching myself out- should I be considered at all with eddy currents in the implant? I feel ...
560 views

### Would there be EMF induced in our body due to electromagnetic radiations?

The experiments of innovative Faraday and Joseph Henry in USA, conducted around 1830, demonstrated conclusively that electric currents were induced in closed coils when subjected to changing magnetic ...
5k views

### Current induced from a magnet moving through a solenoid?

If we had a magnet we move it towards a solenoid a half sine wave current is induced when we make it move back, the other half is induced, inducing an AC current in the solenoid. What if the magnet ...
900 views

### Flux increase due to velocity?

I have a book question I'm trying to understand: The first bit is easy enough. The second part I was confused so I checked the solution: B is into the page. The flux increases as the bar moves to ...
13k views

### Non-conservative electric fields due to changing magnetic flux?

What I read in several places, tells me that, the fact Coulomb's Law follows inverse-square law and gives a force which is radial, implies that a static electric field must be conservative.(In short, ...
3k views

### Charging by induction (and grounding)?

The very familiar phenomenon of charging by induction includes bringing a charged object near an uncharged sphere to induce a separation of charges in it and then grounding the charge (same as the ...
A book which I referenced for Electrical Machinery states that the voltage induced in a conductor inside a magnetic field is given by $$\mathcal{E}=(\mathbf{v} \times \mathbf{B})\cdot \mathbf{l}$$ ...