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Teaching Optics Topics in College Physics Laboratory
Roman Ya. Kezerashvili
New York City College of Technology
The City University of New York
Winter Meeting of the American Association of Physics Teachers
January 7, 2007, Seattle, Washington
AAPT Winter Meeting, Seattle, Washington, January 7, 2007
We propose a list of experiments that could presented at the laboratory class in the second semester of college or university physics courses to study properties of light and electromagnetic wavesThe study of light can be organized into three domains:
• Geometric Optics• Wave Optics• Quantum OpticsThese domains are not strictly disjoint.
AAPT Winter Meeting, Seattle, Washington, January 7, 2007
• Abstract
• We propose a list of designed experiments that could be presented at the laboratory class in the second semester of College and University Physics courses to study properties of light. The study of light can be organized into three domains: geometric optics, wave optics and quantum optics. These domains are not strictly disjoint. In the sets of experiments for the first domain students study the laws of reflection and refraction of light by measuring the dependence of the angles of reflection and refraction on the angle of incident, spherical mirrors and lenses, geometric optics of human eye. In the sets of experiments for the second domain students study the wave properties of light: dispersion, interference, diffraction and polarization. Experiments designed to verify the Malus’s law and measure the Brewster’s angle, determine the wavelength of laser light and study the interference on a transmission and reflection diffraction grating, diffraction on the different size slits and wires. The purposes of experiments for the third domain are to study the spectral lines of different gases, determine the Rydberg’s constant from the spectrum of hydrogen atom, and verify the laws of the photoelectric effect and Einstein’s quantum idea. The objectives of all experiments are to show the real action of physics laws, help students better understand and visualize the subject of the lecture.
AAPT Winter Meeting, Seattle, Washington, January 7, 2007
• I heard, and I forgot
• I see, and I remember
• I do, and I understandChinese Proverb
Lecture
Lecture with Demo
Lab Class
• Around 650 students yearly take these classes
• Usually 24 students in the Lab classes
• 8 setups of each experiment
AAPT Winter Meeting, Seattle, Washington, January 7, 2007
Geometric Optics
Dependence of the Angle of Reflection on The Angle of Incidence
y = 1.0039x
R2 = 0.99890
20
40
60
80
100
0 20 40 60 80 100
Angle of Incidence, q i
An
gle
of
Ref
lect
ion
, q r
Reflection and Refraction of Light by Measuring the Dependence of the Angles of Reflection and Refraction
on the Angle of Incidence
Mirror
Rotated Table
AAPT Winter Meeting, Seattle, Washington, January 7, 2007
Rotated Table
y = 1.5327x
R2 = 0.9999
y = 1.1837x
R2 = 0.9994
y = 1.4006x
R2 = 1
0
0.2
0.4
0.6
0.8
1
1.2
0 0.2 0.4 0.6 0.8 1
sinq r
sinq i
Acrylic
Water
Glass
rsinsin
Law sSnell'
qq ni
Refracted Material:
Glass Water
Acrylic
Geometric Optics
AAPT Winter Meeting, Seattle, Washington, January 7, 2007
Refracted Ethaform
Prism with Styrene Pellets
Refraction and Reflection of Electromagnetic Waves
Receiver
Metal Reflector on
Rotating Holder
TransmitterTransmitter provides 15 mW of coherent, linearly polarized microwave output at awavelength of 2.85 cm.
AAPT Winter Meeting, Seattle, Washington, January 7, 2007
Polarization of Light
Photometer
Polarizer
Physical Optics
AAPT Winter Meeting, Seattle, Washington, January 7, 2007
Polarization of Electromagnetic Waves
Polarizer
Receiver
Transmitter
AAPT Winter Meeting, Seattle, Washington, January 7, 2007
Polarization of Light and Electromagnetic Waves
0
0.2
0.4
0.6
0.8
1
1.2
0 30 60 90 120 150 180
Angle q , Degree
No
rma
lize
d In
ten
sit
y,
I/Io
Series1
Experimental Data
Polarization of Light
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
0 30 60 90 120 150 180
Angle, Degree
No
rma
lize
d In
ten
sit
y q2cosy
Polarization of Electromagnetic Waves
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
0 30 60 90 120 150 180
Angle, Degree
No
rma
lize
d In
ten
sit
y
q2cosyMalus’s law
q20 cosII
Polarization through
Absorption
AAPT Winter Meeting, Seattle, Washington, January 7, 2007
Varification of Malus's Law for Light
y = 9.3769x + 0.2965
R2 = 0.9951
0
2
4
6
8
10
12
0 0.2 0.4 0.6 0.8 1 1.2
Inte
ns
ity
of
Lig
ht,
I, W
/m^
2
q2cos
Varification of Malus's Law for Electromagnetic Waves
y = 0.9333x + 0.0684
R2 = 0.9886
0
0.2
0.4
0.6
0.8
1
1.2
0 0.2 0.4 0.6 0.8 1 1.2
No
rmal
ized
Inte
nsi
ty,
I/Io
Series1
Linear (Series1)
q2cos
Malus’s law
q20 cosII
Polarization through
Absorption
AAPT Winter Meeting, Seattle, Washington, January 7, 2007
Interference: transmitted and reflected
grating
Laser
transmitted grating
CD: Reflected grating
AAPT Winter Meeting, Seattle, Washington, January 7, 2007
y1
y1
y2
y2
Laser
CD
CD holderL
Diffraction scale
Optics bench
Setup for measuring a grating space of a CD
AAPT Winter Meeting, Seattle, Washington, January 7, 2007
Interference,...3 ,2 ,1 ,0 , sin mmd q
,...3 ,2 ,1 ,22
myL
y
m
d
m
m
ym
L
AAPT Winter Meeting, Seattle, Washington, January 7, 2007
Double –Slit Interference of EM Waves
EM WaveTransmitter
EM WaveReceiver
Double Slit
0
1
2
3
4
5
6
7
8
9
10
0 10 20 30 40 50 60 70 80
Angle, q
Met
er R
ead
ing
Run1
Run2
Transmitter
Receiver
AAPT Winter Meeting, Seattle, Washington, January 7, 2007
Photoelectric Effectf
e
h
e
WVs
e
hSlope
f
Vs
Yellow
Green
Blue
Violet
Ultraviolet 1410203.8
1410409.7
1410879.6
1410490.5
1410187.5
AAPT Winter Meeting, Seattle, Washington, January 7, 2007
Geometric Optics
Michelson InterferometerMichelson Interferometer
AAPT Winter Meeting, Seattle, Washington, January 7, 2007
Experimental SetupExperimental Setup
Microwave Transmitter
MicrowaveReceiver
AAPT Winter Meeting, Seattle, Washington, January 7, 2007
Experimental SetupExperimental Setup
Microwave Transmitter
MicrowaveReceiver
AAPT Winter Meeting, Seattle, Washington, January 7, 2007
Experimental SetupExperimental Setup
Microwave Transmitter
MicrowaveReceiver
AAPT Winter Meeting, Seattle, Washington, January 7, 2007
Experimental SetupExperimental Setup
L1=BC
L2=AC
Movable Reflector
MicrowaveTransmitter
Microwave Receiver
Partial Reflector
Reflector
AAPT Winter Meeting, Seattle, Washington, January 7, 2007
Experimental SetupExperimental Setup
Microwave Transmitter
MicrowaveReceiver
AAPT Winter Meeting, Seattle, Washington, January 7, 2007
Experimental SetupExperimental Setup
L1=BC
L2=AC
Movable Reflector
EM WaveTransmitter
EM Wave Receiver
Partial Reflector
Reflector
AAPT Winter Meeting, Seattle, Washington, January 7, 2007
Experimental SetupExperimental Setup
EM waveTransmitter
EM waveReceiver
Reflector
AAPT Winter Meeting, Seattle, Washington, January 7, 2007
Conclusions
• All experiments show the real action of magnetic forces, sources of magnetic fields and magnetic induction, and help students better understand and visualize the subject of the lecture
• Students have more active and independent role in the learning process and develop critical thinking abilities