Today

1
Todays agenda Review of Waves. You are
expected to recall facts about waves from Physics
1135. Youngs 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 ?Lm? 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
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?