Calculate Induced EMF in Circular Loop: Cylindrical Coordinates

In summary, the curl of the induced electric field for a loop moving in a uniform magnetic field can be calculated using the cylindrical coordinate system. The ๐‘ ฬ‚ and ๐œ™ฬ‚ directions cancel out, leaving only the ๐‘งฬ‚ direction for the curl of the electric field. The electric field in the ๐‘งฬ‚ direction and ๐ธ๐œ™ can be expressed as 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)]. To calculate
  • #1
TOUHID11
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TL;DR Summary
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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  • #2
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
 
  • #3
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.
 
  • #4
: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
 

FAQ: Calculate Induced EMF in Circular Loop: Cylindrical Coordinates

1. What is the formula for calculating induced EMF in a circular loop in cylindrical coordinates?

The formula for calculating induced EMF in a circular loop in cylindrical coordinates is given by:
EMF = -N * dฮฆ/dt
Where N is the number of turns in the loop and dฮฆ/dt is the rate of change of magnetic flux through the loop.

2. How do you determine the direction of induced EMF in a circular loop?

The direction of induced EMF in a circular loop can be determined using the right-hand rule. If you point your right thumb in the direction of the magnetic field, and curl your fingers in the direction of the current, your palm will point in the direction of the induced EMF.

3. Can induced EMF in a circular loop be negative?

Yes, induced EMF in a circular loop can be negative. This occurs when the magnetic flux through the loop is decreasing, resulting in a negative change in flux over time. This can happen, for example, when a magnet is moved away from the loop.

4. How does the radius of the circular loop affect the induced EMF?

The radius of the circular loop does not directly affect the induced EMF. However, a larger loop will have a larger area, which means a larger change in magnetic flux can occur, resulting in a larger induced EMF.

5. What is the significance of using cylindrical coordinates in calculating induced EMF in a circular loop?

Cylindrical coordinates are useful in calculating induced EMF in a circular loop because they allow us to take into account the circular shape of the loop and the direction of the magnetic field, which may not be aligned with the x, y, or z axes. This allows for a more accurate calculation of the induced EMF in the loop.

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