Shouldn't Emf generated be Derivative of Flux?

Tags:
1. Sep 20, 2015

Ashman Kumar

Hey, I don't understand why emf generated is not the first derivative. For example I have a graph of magnetic flux through a wire against time. I thought that emf generated was the rate of change of flux, however this doesn't work. Emf=-Dflux/Dtime . In this example I have a y=sinx curve for the magnetic flux through wire and the answer is y=-cosx, which is the integral. Thanks in advance

Attached Files:

• flux.png
File size:
4.3 KB
Views:
140
2. Sep 20, 2015

protonsarecool

It's not the integral, its the negative (!) derivative with respect to time. You even posted the correct formula already. $$E = - \frac{d\,\Phi}{d\,t}$$ You need the minus sign due to Lenz's law.

3. Sep 20, 2015

Ashman Kumar

That was actually quite simple, thanks for your explanation