00:01
In this question, we're going to calculate the induced emf and induced current in a coil, circular coil, that expands within a constant magnetic field.
00:13
So to find the induced emf, we need to remember faraday's law, although we're only going to find the magnitude of this.
00:22
So we just need the magnitude of negative n, n where n is the number of turns times the change in flux divided by the change in time.
00:37
I did forget to specify up here, by the way, that n equals 1 because this is a single turn.
00:43
The flux will be delta ba cosine theta, where theta is the angle between the magnetic field and the normal to the loop of wire, and then divided by delta t.
00:55
And in this question, it's going to be the area that is changing.
01:03
So we'll make it be cos theta delta a divided by delta t.
01:08
And because this is a circular wire, we're going to have pi times r2 squared minus pi times r1 squared for our delta theta, or sorry, delta a, my goodness.
01:26
And i'm going to go ahead and factor out that pi, b cos theta pi times r2 squared minus r1 squared, all divided by delta t...