Microsoft Word - Exp 12 Lasers and Spectra.doc ���� Experiment 12 Lasers and Spectral Emissions of Light � � The concept that electrons occupy only quantized energy levels has revolutionized our...

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Please review physical science lab assignment. Part A, B, C,D need help answering on Page 95 and 96. Use the color lamp chart for Part A. Part B, C and D have instruction on how to calculate.


Microsoft Word - Exp 12 Lasers and Spectra.doc ���� Experiment 12 Lasers and Spectral Emissions of Light � � The concept that electrons occupy only quantized energy levels has revolutionized our understanding of matter. The energy of light can be determined from its wavelength "lambda" (expressed in nm, 109nm = 1 m) and the speed of light "c" (2.9979 x 108 m/sec) and Planck's constant "h" (6.6261 x 10-34 J sec) using: E = hc/� The wavelength of light is associated with the color we see according to the following chart. Wavelength (nm or 10-9m) Color 700 red 590 yellow 505 green 470 blue 410 violet 350 Ultra Violet (invisible) Part A Element Lamps Materials: Hydrogen, argon, neon, mercury, helium and sodium (if possible) emission lamps with spectroscopes Hypothesis: Do elements emit line spectra? Can we identify an element from its line spectra? Observe the hydrogen lamp through the spectroscope. Record the color and wavelength of the bright, prominent lines (3 significant figures). Faint, closely spaced lines are emitted by molecular hydrogen and should not be recorded. You should be able to see at least three lines. Calculate the energy (show your work) using the equation above for each of the 3 observed lines. Make the same observations for the argon bulb, recording wavelength and color of the five brightest lines. Other Lamps: There are 3 other lamps, labeled A, B, and C. Look at the other lamps present and identify the element based on comparison with the chart on the back of your lab book. Each element exhibits its own characteristic absorption line spectrum due to differences in the energy levels of the electrons. When elements are heated in a flame, electrons are promoted to excited states with energy higher than the normal ground state. We can identify many elements based on the characteristic color that is produced when the electrons drop from their excited state to a lower state and emit light. ��������� �� ������ ��� ������� ��������� �� ���� 92 Part B Lasers Materials: laser, holograms, fiber optics, chalk dust or laser spray, diffraction grating Hypothesis: Do holograms project 3D images? What are some ways lasers can be used? In the last part of this experiment we will explore some applications of quantum theory used in the real world. We will focus on the laser. The acronym LASER stands for Light Amplified by Stimulated Emission Radiation. A laser consists of a tube containing a lasing medium with two mirrors on each end. See below. The medium is energized using an electric current, a flash lamp, or even a chemical reaction. The atoms or molecules are energized to their excited state. On the molecular time scale, the molecules slowly return to their ground state. As they do so they emit light energy in all directions. However, a few will by chance emit light energy along the axis of the tube toward one of the mirrors on the ends of the tube. As it does so it runs into other excited molecules. These collisions induce the excited molecules to prematurely return to their ground state emitting light energy along the axis of the tube in step with the original colliding light wave. As these light waves travel up and down the tube reflecting off the mirrors at each pass, they pick up many other light waves by stimulating the emission through collisions. Thus the LIGHT is AMPLIFIED by STIMULATING EMISSION forming RADIATION of light (LASER). One mirror on one end is only partially reflecting. When the light intensity exceeds a certain point the light shoots right through out the end of the laser. The result is a straight monochromatic (all of the same color or wavelength) coherent (all waves matching up or in step) light we call laser light. ���������������� ��� ������ ��������� ������������������ �� ������ �� �� ���� ��� � ��������� �� ������ ��� ������� ��������� �� ���� 93 ���� ����� ����� ������ ����� �������� �������������� ���������� ���� ��������� ���������� ������� �� ���������������������� ��������������������� ������������ �������������������� � � ������������������� ������ �������� ����� ������ ����� ������ �������� ������� � � � �������� �������� ����������������������������� � ��������� ������� ������ ��� ����� �������������� �� �� � ���������������� ���������� ����� ����� ��������������� ��������� � ��������������� ������������� �������� �������������������� ���������������������� ������ ���� � � ��������� ��������� ������������������ ���������� �� ���� �������������������� ! ������ � ������� ����� ������ ���� � ��� � ������� � " � ����������#� ��� � ��� ��������� ������� �� ������� ��������� �� ������������� ��� ��������� ������������ ������� ����$���%����������� �&���������������'�� ������ ����������'�� ����� �(���� ����������� ������������ � �)����� ������� �������������� �)����� ���������������������� ����� ������ �)����������������������������������� ��� ������������������������������������ ������ �)���� ��������� � �� �� �� � ���� ������ �� � ���� ������ � �� ��� ����� � ���� � �� ��� �������� � � �������& ��������� ���������� ���������� ���� � ����������� ������������ �� �� � � �����* ���� ������������������ ������� �� ��������������� ��� ���� � �������� ��� �������* ������� � �� ������������ � ������������� ����� ����� ������� ��������� � �����������*����������������� ��� � ��������+�������������� � ������������������������� � ��������� �� ������ ��� ������� ��������� �� ���� 94 Part C Optical Mirage When two parabolic mirrors are placed on top of each other as shown below, an object placed in the center of the bottom mirror will reflect off of the top mirror, then down to the bottom mirror and produce a virtual image above a hole in the top mirror. This virtual image will appear real but as you go to touch it, nothing is there! Try to grab the pink pig. Draw in the pig on the report sheet where it really is and where it appears to be with the real pig circled. Part D Night Quest Experiment Each student or pair of students will sign out a Night Vision card containing a diffraction grating and line spectra of various night time lights. You are to take this home and at night look at various lights through the diffraction grating hole. You are to identify 4 different kinds of lights by comparing the line spectra you observe through the diffraction grating with the line spectra printed on the card. You should record the location (detail) and the type of light on your lab report. Part E Stoke’s Shift Experiment When an atom absorbs energy at a higher energy and then re-emits at a lower energy, it is called the Stoke’s Shift. The emitted energy is always lower than the absorbed energy. The change in energy is due to the loss of energy due to vibrations. Calculate this loss by using E=hc/� for UV light minus green light of the fluorescent Vaseline glass. Do the same for the blue light of the Canada Dry Tonic water. Do the same for the yellow light absorbed by the light bulb and the red fluorescent light of the yellow and green food colors in alcohol. ��������� �� ������ ��� ������� ��������� �� ���� 95 Experiment 12-Lasers Emissions Lab Report Name: __________________________________ Section: _________________ Part A Element Lamps Element Lamp Color of Line Wavelength Energy Calculations (Hydrogen only) Hydrogen Argon Element A ______________________ Element B ______________________ Element C ______________________ Part B Lasers Lasing medium: _______________ hologram images: _______________ Laser color: _______________ excitation method: _______________ ��������� �� ������ ��� ������� ��������� �� ���� 96 Part C Optical Mirage Part D Night Quest Type of Light from Card Location (No Duplicates) 1. ___________________________________ _____________________ 2. ___________________________________ _____________________ 3. ___________________________________ _____________________ Part E Stoke’s Shift Calculation (Show your work) Energy of UV light = Energy of Green light = Energy of Blue light = Energy of Yellow Light = Energy of Red Light Energy of UV light – Energy of Green light = Energy of UV light – Energy of Blue light = Energy of Yellow light – Energy of Red light = Phys Science 12 Experiment 12 Line Spectra = 700 E=hc/λ = (6.621x10-34Js)(2.9979x108m/s)/(7.00x10-7m) For λ = 700nm (red) E should be something x10-19J (be sure to enter unit of J) Argon Line Spectrum Lamp A Lamp B Lamp C
Answered Same DayJul 03, 2021

Answer To: Microsoft Word - Exp 12 Lasers and Spectra.doc ���� Experiment 12 Lasers and Spectral Emissions of...

Vinay answered on Jul 04 2021
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Microsoft Word - Exp 12 Lasers and Spectra.doc
Experiment 12
Lasers and Spectral Emissions of Light
“The concept that electrons occupy only quantized energy levels has revolutionized our understanding of matter. The energy of light can be determined from its wavelength lambda (
expressed in nm, 109nm = 1 m) and the speed of light c (2.9979 x 108 m/sec) and Planck's constant h (6.6261 x 10-34 J sec) using:
E = hc/L
The wavelength of light is associated with the color we see according to the following chart.
Wavelength (nm or 10-9m)Color
700    red
590    yellow
505    green
470    blue
410    violet
350    Ultra Violet (invisible)
Part A Element Lamps
Materials: Hydrogen, argon, neon, mercury, helium and sodium (if possible) emission lamps with spectroscopes
Hypothesis: Do elements emit line spectra? Can we identify an element from its line spectra?
Observe the hydrogen lamp through the spectroscope. Record the color and wavelength of the bright, prominent lines (3 significant figures). Faint, closely spaced lines are emitted by molecular hydrogen and should not be recorded. You should be able to see at least three lines. Calculate the energy (show your work) using the equation above for each of the 3 observed lines.
Make the same observations for the argon bulb, recording wavelength and color of the five brightest lines.
Other Lamps: There are 3 other lamps, labeled A, B, and C. Look at the other lamps present and identify the element based on comparison with the chart on the back of your lab book. Each element exhibits its own characteristic absorption line spectrum due to differences in the energy levels of the electrons. When elements are heated in a flame, electrons are promoted to excited states with energy higher than the normal ground state. We can identify many elements based on the characteristic color that is produced when the electrons drop from their excited state to a lower state and emit light.”
Part B Lasers
“Materials: laser, holograms, fiber optics, chalk dust or laser spray, diffraction grating
Hypothesis: Do holograms project 3D images? What are some ways lasers can be used?
In the last part of this experiment we will explore some applications of quantum theory used in the real world. We will focus on the laser. The acronym LASER stands for Light Amplified by Stimulated Emission Radiation. A laser consists of a tube containing a lasing medium with two mirrors on each end. See below.
The medium is energized using an electric current, a flash lamp, or even a chemical reaction. The atoms or molecules are energized to their excited state. On the molecular time scale, the molecules slowly return to their ground state. As they do so they emit light energy in all directions. However, a few will by chance emit light energy along the axis of the tube...
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