1. Young’s Double Slit Experiment.
Today’s agenda:
Review of Waves.
You are expected to recall facts about waves from Physics 1135.
Young’s Double Slit Experiment.
You must understand how the double slit experiment produces an interference pattern.
Conditions for Interference in the Double Slit Experiment.
You must be able to calculate the conditions for constructive and destructive interference in the double slit experiment.
Intensity in the Double Slit Experiment.
You must be able to calculate intensities in the double slit experiment.

2. Intensity in the Double Slit Experiment
Our equations for the minima and maxima intensity positions are for the centers of the fringes.
In this section, we calculate distribution of light intensity in the double-slit interference pattern.

3. The derivation of the double-slit intensity equation is not particularly difficult, so read about it in your text if you find derivations helpful for your understanding.
A path length difference L= corresponds to a phase difference of =2.
A path length difference L=m corresponds to a phase difference of =2m.
In general, for non-integral m, the phase difference at P between the waves from S1 and S2 is

4. Why did my previous diagrams show this?
Your text writes the equation for the intensity distribution in the double-slit experiment in terms of the phase difference on the previous slide.
Your starting equation for the intensity is
where I0 is 4 times the peak intensity of either of the two interfering waves:
Why did my previous diagrams show this?