Calculating Magnetic Field from Generator Graph

AI Thread Summary
To calculate the magnetic field from the generator's emf graph, the relationship between emf, magnetic flux, and the number of turns is crucial. The emf is directly proportional to the change in magnetic flux, expressed as emf = -N(dΦ/dt). Using the given values, including the frequency of 2.4 Hz and angular speed of 14.96 rad/s, the formula can be rearranged to solve for the magnetic field B. The calculation provided yields a magnetic field strength of approximately 0.39 T. This approach effectively demonstrates how to derive the magnetic field from the generator's emf data.
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Homework Statement


I have a graph of an emf of a generator vs time, and i know the cross-sectional area per turn is 0.03m^2 and there are 160 turns. From the wave graph I figured out the frequency of the generator is 2.4Hz and the angular speed is 14.96rad/s. I need to figure out the magnetic field.


Homework Equations


e=-NAcos0B/t


The Attempt at a Solution



I found the frequency and angular speed from the graph but I have no idea how to find the magnetic field from a graph. Please help. Thank you.
 
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It's important to realize that the emf is directly proportional to the change of magnetic flux:

\Phi = BS\cos{\omega}t

emf = -N \frac{d\Phi}{dt},

that is:

emf = -NBS \frac{d}{dt}\cos{\omega}t = -NBS\omega\sin{\omega}t

Then rearrange it to get the formula for B.
 
Last edited:
Ok so I rearranged the formula to get B=emf/-NAwsinwt
= 28/(-160)(.03)(14.96)(sin(14.96*.315))
=28/71.808
=0.38993
Is that correct? Thanks!
 

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