00:01
All right, so let's say we have a wire that is bent into a loop and we have some location a, and we have a compass needle here that is pointing in this direction, and we're told north is this direction, and the angle it deflects from north is 17 degrees.
00:16
The distance between the wires, we're told, is 4 .5 centimeters.
00:22
So we wanna know what's the direction of the magnetic field at location a, given this information.
00:27
So what we need is the magnetic field needs to be pointing this way, curling into the wire like this.
00:33
And so at the location a, it's gonna be into the page.
00:40
And we can find the magnetic field strength of the wire because we're told that earth's magnetic field, we'll call this b naught, is about 20 microtesla.
00:52
And so what we'll have is the tangent of theta is gonna equal our magnetic field at this location over b naught...