P58
B2
Diffraction of light through single-slit
S U P P OR T
R OD
T O LIGH T
S E N S OR
R OT AR Y M OT ION
S E N S OR
TO
IN T E R FACE
LIN E AR M OT ION
ACCE S S OR Y
LAS E R
LAS E R BE AM
FIBE R
OP T IC
P R OBE
COM P ON E N T
CAR R IE R
D IFFR ACT ION
S LID E
Equipment Needed
Science Workshop TM Interface
Light Sensor
Rotary Motion Sensor (RMS)
Base and Support Rod
Component Carrier (for mounting
slides)
-
BE N CH
Diffraction Slide, single slits
Laser
Linear Motion Accessory (for
RMS)
Optics Bench
Purpose
The purpose of this laboratory activity is to investigate the wave nature of light by
studying diffraction patterns.
Procedure
Equipment Setup
1 . Mount the laser on one end of the optics bench. Put the component earner about
midway on the optics bench. Place the single-slit diffraction slide on the component
carrier.
2. Turn on the power switch on the back of the laser. Adjust the position of the
laser and the single-slit diffraction slide so that the laser beam passes through one of
the single-slit pairs on the slide and forms a clear diffraction pattern.
NOTE: Use a piece of white paper as a temporary viewing screen to see the
diffraction pattern.
3. Record the slit width "a" of the single-slit pattern you use in the Data section.
4. Align the laser beam with one of the single slits on the diffraction slide. Adjust
the positions of the laser, diffraction slide, and fiber optic probe if necessary so that
the diffraction pattern is at the same height as the fiber optic probe.
5. Put the end of the linear motion accessory into the slot on the side of the RMS.
6. Mount the RMS on a support rod at the opposite end of the optics bench from the
laser.
NOTE: Place the RMS as far from the double-slit diffraction slide as is practical.
7. Orient the sensor so the Linear Motion Accessory with fiber optic probe is
horizontal.
Adjust the sensor so the fiber optic probe is .it the same height as the interference
pattern created by the single-slit.
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P58
B2
Data recording
Move the Linear Motion Accessory so the maximum at one edge of the diffraction
pattern is near the edge of but not quite on the end of the fiber optic probe.
1 . Click the REC to begin collecting data.
2. Slowly and smoothly, move the Linear Motion Accessory so that the maxima of
the diffraction pattern move across the end of the fiber optic probe.
3. When the entire diffraction pattern has been measured, click the STOP button to
stop collecting data.
Run #2 will appear in the Data List in the Experiment Setup window.
4.
Turn off the laser.
Analyzing the data
1 . Click the Graph to make it active. Click the Autoscale button to rescale the
Graph to fit the data.
2. Examine the shape of the plot of light intensity versus position.
The Graph will display the most recent run of data. Use the Add Plot Menu to create
a second plot on the Graph.
3. Click the Add Plot Menu button Select Analog A, Intensity from the Add Plot
Menu.
Both plots will show the most recent run (Run #2) of data. Use the DATA Menu in
the top plot of the Graph to display Run #1.
4. Click the DATA Menu button in the top plot of the Graph. Select No Data to
clear Run #2. Click the DATA Menu button again and select Run #1.
The top plot will display Run #1 and the bottom plot will display Run #2.
5. Click the Autoseale button again to rescale the Graph, if needed.
6. Slit Width (a) of the single-slit is
.
Complete the following table:
Trial
Silt width(a)
Intensity
Conclusion
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