Induced EMF in a small volume of a conductor?

In summary, the induced EMF is all around the conductor, but it is limited to the area the magnetic field interacts with.
  • #1
PhiowPhi
203
8
Assume we have the following copper slab, with volume ##V##, and introduced a magnetic field covering a small area of it like so:

RNC1wTP.png

There is change in magnetic flux(##\phi##) due to the magnetic field increasing/decreasing, and via Faraday & Len'z law of electromagnetism, there is an induced EMF(##- \epsilon ##) to oppose that change, and with the conductor's resistance(##r##) an induced current(##I##).

One thing that I'm struggling with, is knowing/understating where the induced EMF is bound to? Is the induced EMF all around the conductor like so:
HsN3nUn.png

Where if I placed a volt-meter anywhere on the top part (A) and the bottom part, the voltage would be the same any point there?
Or , is the induced EMF limited to the area the magnetic field interact's with like so:
7B8O3ho.png

The blue rectangle represents the magnetic field, and r, the resistance of the whole slab.
Likewise, will induced current be focused to that area the magnetic field interacts with, or the entire slab?

One thing I'd like to add, if we introduced and exterior Voltage source to the slab, with the induced EMF, would it be in series?
A5lteD6.png

The total voltage if they we're in a circuit, and they are connected to one another the net-voltage in the circuit would be:

##V_n## = ##V## - ##\epsilon## ?
 
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  • #2
PhiowPhi said:
Assume we have the following copper slab, with volume VV, and introduced a magnetic field covering a small area of it like so:
If I understand you correct, that some magnetic changing flux, repesented by XXXXXXX, is induced perpendicular through the slab, you will get a circulating emf around the flux:

circulationemf ⋅ ds = dΨ/dt , Ψ is the flux , s is a surrounding path ( the edge of the blue rectangle ).

You will get Eddy-voltage and Eddy-current.
 
  • #3
Hesch said:
You will get Eddy-voltage and Eddy-current.

If connected to a circuit it would be Eddy voltage & induced voltage(one via circuit and one via the surface of the conductor)?
Also, if there is current running through the conductor from a source(V+) it would be in series and oppose the applied voltage as diagramed in the last image?
 

1. What is induced EMF in a small volume of a conductor?

Induced EMF (electromotive force) is the voltage that is generated in a conductor when it is exposed to a changing magnetic field. This voltage is induced due to the movement of electrons in the conductor, which creates a flow of electricity.

2. How is induced EMF calculated?

Induced EMF is calculated using Faraday's law of electromagnetic induction, which states that the induced EMF is equal to the rate of change of magnetic flux through the conductor. It can be calculated using the formula E = -N * dΦ/dt, where E is the induced EMF, N is the number of turns in the conductor, and dΦ/dt is the change in magnetic flux over time.

3. What factors affect the magnitude of induced EMF in a conductor?

The magnitude of induced EMF is affected by several factors, including the strength of the magnetic field, the rate of change of the magnetic field, the angle between the conductor and the magnetic field, and the length and cross-sectional area of the conductor.

4. How does Lenz's law relate to induced EMF?

Lenz's law states that the direction of the induced EMF will be such that it opposes the change in magnetic flux that caused it. This means that the induced current will flow in a direction that creates a magnetic field that opposes the change in the original magnetic field.

5. What are some practical applications of induced EMF?

Induced EMF has many practical applications, including power generation through the use of generators, electric motors, transformers, and induction cooktops. It is also used in various sensors, such as magnetic field sensors and current sensors, and in devices such as magnetic levitation trains.

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