Magnetic flux in a coil, find current

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SUMMARY

The discussion focuses on calculating the magnetic flux and current in a circular coil rotating in a magnetic field. The coil has a radius of 0.35 meters, rotates at a frequency of 120 Hz, and is subjected to a magnetic field of 0.8 Tesla with 340 turns and a resistance of 50 ohms. Key calculations include the initial magnetic flux at t=0, the electromotive force (emf) as a function of time, and the peak and RMS currents through the coil and capacitor. The equations utilized include flux = NBAcos(angle) and i = e/R.

PREREQUISITES
  • Understanding of Faraday's Law of Electromagnetic Induction
  • Familiarity with basic circuit theory, including Ohm's Law
  • Knowledge of AC circuit analysis, including RMS and peak current calculations
  • Concepts of magnetic flux and its calculation in rotating systems
NEXT STEPS
  • Learn about Faraday's Law and its applications in electromagnetic systems
  • Study AC circuit analysis techniques, focusing on peak and RMS current calculations
  • Explore the relationship between frequency, inductance, and impedance in coils
  • Investigate energy storage in capacitors and the effects of resistance in circuits
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Students studying electromagnetism, electrical engineers, and anyone involved in circuit design and analysis, particularly in applications involving rotating coils and magnetic fields.

hugage
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Homework Statement



1.) Problem (exam question that I got wrong and want to figure it out)
A circluar coil of radius a=.35m rotates at a frequency of 120 hz in a constant magnetic filed of B=.8T. The axis of rotation is perpendicular to the field the coil has N =340 turns it has a resistance R=50 ohms
a.) what is flux thru coil t=0 if the normal vector of the coil is at an angle of 45 degrees to magnetic filed?
b.) suppose the coil starts rotating, what is its flux as a function of time?
c.) what current runs through the coil? peak current? RMS current?
d.)if coil connected to capacitor, what is current thru cap.(ignore the resistance)? peak current? what energy is stored in the capa.? where is it stored?
e.) answer the same for a resistor.



Homework Equations


i = e/R
flux = NBAcos(angle)
e = - delta flux/ delta t


The Attempt at a Solution



a) flux = NBAcos(angle) = 340 x .8 x pi x (.35) ^2 cos(45) = 74.01
b) e = - delta flux / delta t, so - 74.01 x d/dt where do I get time, is it t = 1/f f = 120 hz?
 
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Could you maybe draw a picture? I don't understand how this is set up, which direction the field is pointing, which direction the coil is aligned in, and which way it is spinning.
 
I wish I could but that is all the information I was given. I been banging my head on the desk for hrs trying to understand.
 

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