# Average induced EMF

## Homework Statement

The area of a 100 turn coil oriented with its plane perpendicular to a 0.28 T magnetic field is 4.3×10−2 m^2.
Find the average induced emf in this coil if the magnetic field reverses its direction in 0.36 s.

## Homework Equations

E = -N (flux - flux initial)/(t-to)

## The Attempt at a Solution

I'm actually not even sure I am using the correct equation. It is the only one I see that uses N. But I'm not sure how I would find an initial time and even a flux. Help?

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kuruman
Homework Helper
Gold Member
It is the correct formula.
Look up the definition of flux.
Note that the denominator is t - t0. How does "... reverses its direction in 0.36 s" relate to t - t0?

ok i found something in which i can use BAcostheta instead of flux... would that work? and i guess t would be 36 and initial would be zero?

kuruman
Homework Helper
Gold Member
Correct on both accounts. What is cos(theta) here?

is it just 1?

also would A stay the same? and how to find B? or do you have to find B initial?

kuruman