00:01
Okay, so we have a piece of charge that has uniform density along this line.
00:05
They call it rho l, but i'm going to call it lambda.
00:15
Basically, charge over length.
00:21
That way, i'm not going to confuse the charge density with the cylindrical coordinate.
00:27
Okay, so what we're interested in, we're going to take a point out here in the xy plane, plane where z equals zero.
00:39
And we're interested in knowing what the electric field is there.
00:43
So that distance from the axis out to that point is the cylindrical radial coordinate.
00:51
And then the cylindrical angle is measured from the x -axis.
00:57
So that's our angle phi.
01:04
Remember this angle is measured in the xy plane.
01:08
Okay, so we're taking de, e, calculating this, calculating e by an integral, here's what we gotta do.
01:19
We have that one over four pi epsilon naught, lambda dz is our dq, and then we got that distance squared, one over rho squared plus z squared.
01:30
And then we also have to have a unit vector that points in the direction of the electric field...