00:01
Has to design a diffraction rating such that visible light that's passing through it will have a maximum dispersion angle of 27 degrees for first -order interference maximum.
00:14
So visible light spans the wavelength range from 380 nanometers which corresponds to violet light, up to 750 nanometers, which corresponds to red light.
00:24
So we need to find the number of slits per centimeter such that the angle of dispersion or even 27 degrees.
00:36
All right, so we know that for greater wavelengths, we have greater dispersion angles.
00:44
So in order to keep the maximum below 27 degrees, we'll have to set theta equal to the definition of the dispersion angle, which is m -lamda over d, and solve for d, such that we can satisfy theta being equal to 27 degrees.
01:06
And then from d, we'll use the formula, d is equal to one over the number of slits per meter.
01:14
So we'll solve for this slits from centimeter.
01:17
All right, so with this equation, we're talking about first order peaks, so i'm just going to be equal to one.
01:24
So we can solve for d.
01:28
First, we're gonna plug in 27 degrees, and then this can be equal to the arc sign of lambda, which is going to be lambda r, 750 nanometers over d...