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**1. Homework Statement**

Two concentric circular coils of wire lie in a plane. The larger coil has 61 turns and a radius of

*a*= 7.40 cm. The smaller coil has 58 turns and a radius of

*b*= 0.95 cm. The current in the larger coil has a time dependence as shown in the figure.

Picture and graph:

http://imgur.com/fHB07bx

Approximately what is the magnitude of the EMF induced in the small coil at

*t*= 8 s?

**2. Homework Equations**

ξ=(d/dt)∫B⋅dA

∫B⋅dl=μ*I

**3. The Attempt at a Solution**

I tried taking the derivative of the slope given with respect to time

So -15*e^(-3t)

And multiplying that by the area of the small coil and the number of turns in the small coil.

I don't really know where to go from there.

I tried taking the derivative of the slope given with respect to time

So -15*e^(-3t)

And multiplying that by the area of the small coil and the number of turns in the small coil.

I don't really know where to go from there.

**I got 3.78E-12 V and thats not right**