00:01
Okay, so we're looking at the rather fron scattering experiment, and we want to determine this relationship between the impact parameter b and the angle of the scattering angle.
00:19
So let's first look at what these two parameters are.
00:25
So if we have a nucleus, and so we'll say this is a nucleus, and then you have an alpha particle traveling toward it.
00:38
So it's going to travel along some trajectory, and then it's going to be deflected as it gets near that nucleus.
00:50
And so the deflection is described by this angle here, theta.
00:59
And b is just this distance from the line that would directly hit the nucleus and its actual path.
01:09
So this is b.
01:12
And so the larger b is, the smaller this deflection is.
01:18
And so just for example, if we were traveling here at a smaller b, we're going to have a larger deflection angle like that.
01:34
And so let's look at the relationship, the mathematical relationship between b and theta.
01:43
So b is equal to z1, z2, x squared over 8 pi, epsilon, k times a cotangent of theta over 2.
02:05
Okay, and so all of this here is just constant for some given particle, or a set of particles.
02:17
And so we can ignore that for this problem, or for this relationship, we can just say, b is proportional to cotangent of theta over 2...