(New tips are continually added to these pages. Check back in a few months' time for more)

TOPIC 8: Waves, Superposition, Interference and Diffraction

Tip 1:

The Diffraction Grating is more closely related to Young's Double Slit than to Diffraction.

In fact, the Diffraction Grating can be considered as a "Young's Multiple Slits"; or alternatively, Young's Double Slit is a "Two-Slit Diffraction Grating".

So the formula d sin q = nl is applicable to both Young's double slit as well as to Diffraction Grating. But the formula fringe separation x = lD/d is only applicable to Young's double slit and not the Diffraction Grating, due to the relatively large angles involved in the Diffraction Grating.