00:01
In each of these situations, we're asked to find the direction of either a current and magnetic force or a magnetic field.
00:08
And we're asked to do that using either the first right -hand rule, the second right -hand rule, or lenses law.
00:13
So i've written those down here on the right -hand side.
00:17
Sorry, lenses law is getting cut off a little bit.
00:20
So for situation a, we want to know the direction of the magnetic force.
00:25
In order to find the direction of the magnetic force, usually we want to use the right -hand force.
00:30
The second right hand rule, so our thumb should be in the direction of the current.
00:36
The magnetic force will be in the direction of the pointer finger, and then our middle finger, which will be perpendicular to those two, will show the direction of the force.
00:46
So the direction of the force ends up being sort of this direction, and we used the right hand rule number two to figure that out.
01:00
For part b, we want to know the direction of the force, and we're told that that positive sign means the charge is positive.
01:10
So again, we're finding a force.
01:12
We're going to use right -hand rule two, put our thumb in the direction of the current or the direction of motion of that positive charge, because that's generally the direction of the current.
01:21
And then we want to put our pointer finger in the direction of the magnetic field.
01:27
And so that means that the direction of the force is going to be, at least the way that my hands are doing it, it's going to be sort of out of the page.
01:49
So i'll draw that as a circle with a dot in the middle, and we used right -hand rule number two again for this one.
01:58
For situation c, we want to know the direction of the magnetic fields on each...