4.7 Diffraction Gratings

Adding More Slits

Results in more separate beams of light with brighter snd narrower fringes. Dark fringes become darker

Diffraction Grating - Interference Pattern

When monochromatic light passes through a diffraction grating, it creates sharp, bright fringes at specific angles.

The central maximum is the zero-order line.

First-order lines appear on either side, then second, third, etc.

This shows constructive interference at specific angles.

Measuring Wavelength with a Diffraction Grating

The wavelength of light can be found using:

nλ=dsin⁡θ

Where:

n = order of the fringe

λ = wavelength

d = distance between slits

θ = angle to the normal for nth-order fringe