Calculating Magnetic Fields and Induced EMFs: Help Needed!

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SUMMARY

The discussion focuses on calculating the magnetic fields and induced electromotive forces (EMFs) from a power line carrying 50Hz alternating current. The magnetic field at a coil with 1500 turns and an area of 5cm², positioned 10m from the wire carrying 800A, is determined using the formula B = [N(mu_0)I]/2R. To find the induced EMF, the user correctly identifies that the change in magnetic flux over time is essential, utilizing the relationship dI/dt = 2πfI for alternating current. The conversation highlights the importance of understanding the relationship between magnetic fields and induced EMFs in AC circuits.

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  • Understanding of Ampère's Law and magnetic fields
  • Familiarity with Faraday's Law of Electromagnetic Induction
  • Knowledge of alternating current (AC) concepts
  • Basic proficiency in calculus for understanding derivatives
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Hey
I'm wondering if someone can help me out with this question.

Q: In order to measure the magnetic fields produced by the power lines carrying 50Hz alternating current, a coil consisting of 1500 turns of area 5cm^2 as constructed. Suppose that there is a single power line carrying a current which has an amplitude of 800A and that the coil is 10m from the wire.
a) What is the magnitude of the magnetic field at the coil
I found this using B =[N(mu_0)I]/2R
b) What is the magnitude of the induced emf in the coil?

I'm stumped on B :confused: could anyone point me in the right direction? I was using the idea that change in flux over time can be used to find induced emf and that in an alternating curret dI/dt=2*pi*f*I - but the problem is that i don't know where to go from there.

Thanks in advance!
 
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The magnetic field is not constant.
Write the equation for the current as a function of time.
 
thanks for the quick reply - but i don't quite understand how this ties in with finding the emf using the change in flux over the change in time.
 
oh i see now! sorry - I wasn't thinking properly! Thanks again :)
 

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