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## Homework Statement

A loop of wire with an area 1cm^2 is centered within a larger loop of area 1m^2. Apower supply is generating current through the larger loop described by the function:

I(t) = 40A * cos(2t/s * 2pi/5)

Calculate EMF at time t = 3s

## Homework Equations

Magnetic flux = BAcos(theta)

EMF = d/dt Magnetic Flux = d/dt BAcos(theta)

B = ui/2r = (u/2r) 40A * cos 2t/s * 2pi/5)

u = permeability of free space = 4pi * 10^-7

r = sqrt(area of circle/pi)

## The Attempt at a Solution

Some of the work done above, I set the equation of B into the emf then took the derivative with respect to time.

EMF = 57 d/dt uA/2r cos(3t - 2pi/5)^2

EMF = 57*3* uA/2r cos(6t- 2pi/5)

I confused myself over which A I was referring to and which radius as well. Thinking about this it makes sense that A is the smaller loop's area and r is the bigger loop's radius.

Does this look correct?

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