Physics Learning Goal 9

1. {
Double-Slit
Interference
By Mike Yoon
Physics 101 203
14334149

2.  Early 19th century, Thomas Young performed
an experiment that proved light has wave
properties.
History

3. Visual representation of
the experiment

4.  The waves in the picture represent the peak of a
wave.
 When these peaks overlap another peak, the
wave is exactly in phase.
 The straight lines in the picture represent bright
spots due to the constructive interference from
the peaks and valleys overlapping.

5.  Since the waves from the two slits are from the
same light source, the waves are exactly in sync
but comes out in different holes.
 Therefore only a phase difference differs from
these two waves.

6.  The constructive interference occurs when
dsin(theta) = m times wavelength
 The destructive interference occurs when
dsin(theta) = (m+ ½) times wavelength
 Where m is an interger
 d is the distance between two slits.
 Theta is the angle that the bright spot appears
on the screen.

7.  https://www.youtube.com/watch?v=Pk
6s2OlKzKQ&spfreload=10
Great youtube video on
Double-Slit Interference

8.  1. The distance between the two slits are
2.56 x 10^-5 m, the wave length is 550 nm while
m is 1. Find the angle of the constructive and
destructive points.
Practice problems

9.  Theta = 0.021486 rad
Answers