teaching optics topics in college physics laboratory roman ya. kezerashvili new york city college of...

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

Diffraction on a Wire and a Single Slit

AAPT Winter Meeting, Seattle, Washington, January 7, 2007

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

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