Calculate Induced EMF in Circular Loop: Cylindrical Coordinates

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SUMMARY

The discussion focuses on calculating the induced electromotive force (EMF) in a circular loop using cylindrical coordinates while moving in a uniform magnetic field. The curl of the induced electric field is determined to be in the ๐‘งฬ‚ direction, leading to the equation โˆ‡ร—๐ธโƒ— =๐‘งฬ‚ [1/๐‘Ÿ โˆ‚/โˆ‚๐‘Ÿ (๐‘‰๐‘–๐‘›๐‘‘๐‘ข๐‘๐‘’๐‘‘/2๐œ‹๐‘Ÿ)]. The induced voltage is expressed as ฯ†=B*ฯ€*rยฒ*cos(2*ฯ€*s*t), where 's' represents the speed in rotations per second (rps). The relationship between EMF, current, and resistivity is also established, with the formula I=Emf/Zloop and E=ฯ*J.

PREREQUISITES
  • Cylindrical coordinate system
  • Electromagnetic theory, specifically Faraday's law of induction
  • Understanding of curl in vector calculus
  • Basic electrical engineering concepts, including resistivity and current density
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  • Study the application of Faraday's law in dynamic systems
  • Learn about the mathematical properties of curl in vector calculus
  • Explore the relationship between magnetic flux and induced EMF in rotating systems
  • Investigate the effects of resistivity on induced current in conductive loops
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Students and professionals in electrical engineering, physicists studying electromagnetism, and anyone involved in the analysis of induced EMF in rotating systems.

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TL;DR
How can I express the induced EMF in terms of the radius of the loop, through a uniform yet changing B field, in order to calculate the curl of the induced electric field?
In order to calculate for the curl of the induced electric field for a loop moving in a uniform magnetic field, and using the cylindrical coordinate system for a curl, it's my understanding that since the B field is in the ๐‘งฬ‚ direction, then so is the partial time derivative of B, and therefore its curl. So in terms of cylindrical coordinate system, the ๐‘ ฬ‚ , ๐œ™ฬ‚ cancel out and with respect to electric field the ๐ธ๐‘  and ๐ธ๐‘ง is simply zero. So we are left with the curl of the electric field in the ๐‘งฬ‚ direction and the electric field in the ๐ธ๐œ™. And we ultimately end up with:
โˆ‡ร—๐ธโƒ— =๐‘งฬ‚ [1/๐‘Ÿ โˆ‚/โˆ‚๐‘Ÿ (๐‘‰๐‘–๐‘›๐‘‘๐‘ข๐‘๐‘’๐‘‘/2๐œ‹๐‘Ÿ)]
So here, how do I write the ๐‘‰๐‘–๐‘›๐‘‘๐‘ข๐‘๐‘’๐‘‘ in terms of s, to calculate for the partial "s" derivative, and therefore calculate the magnitude of the curl. If there's any conceptual or calculation errors, please do suggest where I have gone wrong.
 
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The magnetic flux has to be the product of B and the projection of the loop area on a surface perpendicular to B. ฮฑ=2*pi()*s*t
loop rotating in magnetic field.jpg
 
Sorry. I forgot to mention:
Emf=-dฯ†/dt ; ฯ†=B*pi()*r^2*cos(2*pi()*s*t)^2 ;s=speed [rps]
I=Emf/Zloop
E[electric field]=ฯ*J [current density];ฯ=loop resistivity.
J=I/loop cross section area.
 
:oops:Correction:

Let's say the loop rotates about a diameter with s rotations per second[rps].

Then the loop projection area will be ะฟ*r^2*cos(ฮฑ)

ฮฑ=2*ะฟ *s*t and the magnetic flux will be:

ฯ†=B*ะฟ*r^2*cos(2*ะฟ*s*t)

*=multiply by [x] as in Microsoft excel
 

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