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## Homework Statement

A magnetic field with the time dependence shown in the figure below is at right angles to a N=197 turn circular coil with a diameter of d=4.2 cm.

What is the induced EMF in the coil at t=7.5ms in mV?

**See attached graph**

## Homework Equations

|EMF|= N*|change in magnetic flux/change in time|

## The Attempt at a Solution

First Attempt:

I first found Area by pi*(.042m/2)^2 and got 0.001385m^2. Then, I found the slope of the line between 5 and 10 ms, which was -0.006 T/ms. Then, I multiplied this slope by 7.5ms to see what the magnetic field at 7.5ms was, and I got -0.45T. Then, I used this value to find the magnetic flux which was (0.001385m^2)(-0.045T) and got -6.235*10^-5. Then, I took this value, divided by 7.5ms, and got -0.00831. Then, I multiplied this by 197 and got -1.63707 V. I divided this by 1000 and got -0.001637mV, but this answer is not being accepted.