00:01
All right, so let's say we have a sheet of current with a thickness or a height b, and we're told that there's a current density j, which is basically just some constant j naught here.
00:15
And so we want to find the magnetic field if the current density is uniform.
00:21
We want to find the magnetic field inside and outside the loop, presumably.
00:27
So outside the loop, if the sheet is like infinite in the y direction, so it has an infinite extent, our amperian loop we can look can draw like this.
00:39
The magnetic field is going to be going this way and then this way above and below the sheet.
00:47
And in fact, there's basically no...
00:49
We're not worried about the magnetic field there.
00:51
So if we draw an amperian loop that intersects the field at these two points like this, then what we'll have is our integral of b dot dl around this loop...