• Double and Single slit patterns
•
•
Ex: In a double slit experiment, red light is
projected through two slits that are spaced
0.25mm apart. The pattern appears on a wall 4.0
metres away. A distance of 4.2 cm is measured
across 4 bright fringes. What is the wavelength
of the light?
Single Slit Diffraction Pattern
• So far we have looked at the pattern created by
waves passing through two narrow slits. But even
when light passes through a single slit, we can see
a pattern of light and dark bands
• This can be explained by modelling the slit as a
number of small point sources
•
•
Make a chart comparing the equations:
Double Slit
Maxima
Minima
Separation of adjacent
minima
Single Slit
When looking at a double slit pattern, what you
often see is the superposition of the single and
double slit patterns.
Example:
How many minima will be produced when red
light from a helium-neon laser of wavelength
630 nm passes through a single slit with width
5.5x10-6m?
Homework:
Page 484 #1-8 but some of these are pretty
repetitive. If you can do a couple of 1, 2, 4-8
then you are in good shape. #3 is a good theory
one.
Page 519 Calculations 1-6 as needed. #5 is a bit
harder. Be sure you can do #12