This document discusses light wave interference and the conditions required for it to occur. It describes how light waves from multiple sources can interfere to produce bright and dark fringe patterns. The bright fringes indicate constructive interference where wave amplitudes combine, while dark fringes represent destructive interference where waves cancel out. For interference to take place, the light sources must be coherent and monochromatic, meaning they have a constant phase difference and same wavelength.

1. Interference of
Light
By: JaLesa Oglesbee and Kaley Ernst

2. Objectives
● Describe how light waves interfere with
each other to produce bright and dark
fringes.
● Identify the conditions required for
interference to occur.

3. Introduction
● In this presentation we will be talking about
light wave interference.
● We will talk about what fringe patterns are
and what they produce .
• We will describe and identify the conditions
required for interference to occur.

4. Fringe Pattern
● Interference fringe pattern is a pattern and
bright and dark lines.
● The bright lines indicate constructive
interference.
● The dark lines indicate destructive
interference.

5. Fringe Pattern Continued..
•
The bright fringe in the middle of the
diagrams is caused by constructive
interference of the light from the two slits
traveling the same distance to the screen.
•
It is known as the “zero-order fringe”.

6. Lets Take A Closer Look
• http://www.dnatube.com/video/1707/Dou
ble-slit-theory-Quantum-Physics-Animation

7. Interference of Light Waves
• The light wave’s color, direction, and speed
•
•
can be changed by interference from other
objects.
If it is a constructive wave pattern the
amplitude will increase.
If the wave pattern is destructive the wave
or waves would decrease in amplitude, or
cancel out in certain cases.

8. Conditions in Which Interference can
Occur.
• The sources must be coherent, which
means, they must obtain a constant phase
difference with respect to each other.
• The sources should be monochromatic,
which is when they have the same
wavelength.

9. Questions ???
• What are the different types of
•
•
•
•
•
•
Interference?
What is a fringe pattern?
If the top of one wave meet the bottom of
another wave, what happens?
The place where the two tops of a wave
meet is?
What happens when they cancel?
What if you only have one slit?
How is marbles different from waves on a
second slit?

10. Resources
http://www.dnatube.com/video/1707/Doubl
e-slit-theory-Quantum-Physics-Animation
http://web.utk.edu/~cnattras/Phys250Fall20
12/modules/module
%201/diffraction_and_interference.htm
http://www.calstatela.edu/faculty/gzhao2/Physi
cs212lectures/Chapter37lecture.pdf