00:02
Okay, so this problem, we have our grading, we have our center line.
00:15
We're going to have a red line at 656 nanometer wavelength, which is going to put it, its first order will be a little bit higher than the blue violet line, which would be about here.
00:35
And the rest of the waves will be between them.
00:39
Okay, so we just need to calculate the thetas between those.
00:42
So the red line theta, oh, our d value, let's do that.
00:47
So let's put that in black because it's going to be used for both of them.
00:51
So d value, we're going to do one out of every, there's 4 ,500 groups per centimeter...