Experimental Setup
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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 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 waves The study of light can be organized into three domains: • Geometric Optics • Wave Optics • Quantum Optics These 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 • Around 650 students yearly take these classes • Usually 24 students in the Lab classes • 8 setups of each experiment • I heard, and I forgot • I see, and I remember • I do, and I understand Chinese Proverb AAPT Winter Meeting, Seattle, Washington, January 7, 2007 Lecture Lecture with Demo Lab Class Geometric Optics Reflection and Refraction of Light by Measuring the Dependence of the Angles of Reflection and Refraction on the Angle of Incidence Rotated Table 100 80 qr Mirror Angle of Reflection , Dependence of the Angle of Reflection on The Angle of Incidence 60 y = 1.0039x R2 = 0.9989 40 20 0 0 20 40 60 Angle of Incidence, AAPT Winter Meeting, Seattle, Washington, January 7, 2007 80 qi 100 Geometric Optics Refracted Material: Glass Water Acrylic Rotated Table 1.2 Glass y = 1.5327x R2 = 0.9999 1 sin q i Snell' s Law sin q i nsin q r 0.8 0.6 Water y = 1.1837x R2 = 0.9994 0.4 0.2 0 0 0.2 0.4 0.6 sinq r AAPT Winter Meeting, Seattle, Washington, January 7, 2007 0.8 1 Acrylic y = 1.4006x R2 = 1 Refraction and Reflection of Electromagnetic Waves Transmitter Receiver Refracted Metal Ethaform Reflector on Prism with Rotating Styrene Holder Pellets AAPT Winter Meeting, Seattle, Washington, January 7, 2007 Transmitter provides 15 mW of coherent, linearly polarized microwave output at a wavelength of 2.85 cm. Physical Optics Polarization of Light Photometer Polarizer 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 Polarization through Absorption Malus’s law 1.2 Normalized Intensity, I/Io Normalized Intensity Polarization of Electromagnetic Waves I I 0 cos 2 q Polarization of Light 1 0.8 1.2 y cos 2 q 0.61 0.8 0.4 0.6 30 30 y cos 2 q 1.2 1 0.8 0.6 0.4 0.2 0 -0.2 0 30 60 90 120 150 Series1 0.4 0.2 0.2 00 -0.2 00 Normalized Intensity Experimental Data 180 Angle, Degree AAPT Winter Meeting, Seattle, Washington, January 7, 2007 60 90 120 120 150150 180180 60 90 Angle qDegree , Degree Angle, Varification of Malus's Law for Electromagnetic Waves Normalized Intensity, I/Io Polarization through Absorption Malus’s law I I 0 cos 2 q 1.2 1 Series1 Linear (Series1) 0.8 0.6 0.4 y = 0.9333x + 0.0684 0.2 R2 = 0.9886 0 0 0.2 0.4 Intensity of Light, I, W/m^2 Varification of Malus's Law for Light 12 10 8 6 4 y = 9.3769x + 0.2965 R2 = 0.9951 2 0 0 0.2 0.4 0.6 cos q 2 0.8 1 1.2 AAPT Winter Meeting, Seattle, Washington, January 7, 2007 0.6 2 cos q 0.8 1 1.2 Interference: transmitted and reflected grating CD: Reflected grating Laser transmitted grating AAPT Winter Meeting, Seattle, Washington, January 7, 2007 Laser Optics bench y2 y1 y1 y2 CD L CD holder Diffraction scale Setup for measuring a grating space of a CD AAPT Winter Meeting, Seattle, Washington, January 7, 2007 Interference d sin q m , m 0, 1, 2, 3,... ym L ym d , m L2 y 2 m AAPT Winter Meeting, Seattle, Washington, January 7, 2007 m 1, 2, 3,... Double –Slit Interference of EM Waves EM Wave Receiver Transmitter EM Wave Transmitter Double Slit Receiver 10 9 Meter Reading 8 7 6 5 4 3 Run1 2 Run2 1 0 0 10 20 30 40 Angle, q 50 AAPT Winter Meeting, Seattle, Washington, January 7, 2007 60 70 80 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 Effect Vs W h f e e Vs Slope h e f AAPT Winter Meeting, Seattle, Washington, January 7, 2007 Yellow 5.1871014 Green 5.4901014 Blue 6.8791014 Violet 7.4091014 Ultraviolet 8.2031014 Geometric Optics Michelson Interferometer AAPT Winter Meeting, Seattle, Washington, January 7, 2007 Experimental Setup AAPT Winter Meeting, Seattle, Washington, January 7, 2007 Experimental Setup Microwave Receiver Microwave Transmitter AAPT Winter Meeting, Seattle, Washington, January 7, 2007 Experimental Setup Microwave Receiver Microwave Transmitter AAPT Winter Meeting, Seattle, Washington, January 7, 2007 Experimental Setup Microwave Receiver Microwave Transmitter AAPT Winter Meeting, Seattle, Washington, January 7, 2007 Experimental Setup Reflector Movable Reflector L1=BC L2=AC Partial Reflector Microwave Receiver Microwave Transmitter AAPT Winter Meeting, Seattle, Washington, January 7, 2007 Experimental Setup Microwave Receiver Microwave Transmitter AAPT Winter Meeting, Seattle, Washington, January 7, 2007 Experimental Setup Reflector Movable Reflector L1=BC L2=AC Partial Reflector EM Wave Receiver EM Wave Transmitter AAPT Winter Meeting, Seattle, Washington, January 7, 2007 Experimental Setup EM wave Transmitter EM wave Receiver 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 AAPT Winter Meeting, Seattle, Washington, January 7, 2007
