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forestmine
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Homework Statement
An inductor has a current I(t) = (0.480 A) cos[(280 s-1)t] flowing through it. If the maximum emf across the inductor is equal to 0.490 V, what is the self-inductance of the inductor?
Homework Equations
ε = -L*di/dt
The Attempt at a Solution
I would have that this would be as easy as using the above equation, and taking a derivative as necessary. The one thing that throws me is the value of t and the fact that it is unknown.
So, what I did was,
ε = LdI(t)/dt
Taking the derivative of I(t), I get
dI(t)/dt = -(.48)(1/280)sin(1/280*t)
If I even did that correctly, I still don't have a value of t in order to solve for L. I know that the maximum emf across the inductor will occur right at t=0, right? As the current reaches a steady value, dI/dt goes to 0, at which point the inductor acts as a wire and there is no emf across it.
But if that's the case, and this max emf of .49 V occurs at t=0, then sin(0) = 0, and L = 0.
I think I'm completely missing something, here.
Any help in the right direction would be great.
Thanks!