Diffraction of Light Through Single-Slit

P58

B3

Interference of light through double-slit and multiple slit

Equipment Needed

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P58

B3

-Science Workshop TMInterface Diffraction

-Light Sensor

-Rotary Motion Sensor (RMS)

-Base and Support Rod

-Component Carrier (for mounting slides)

-Diffraction Slide, double slits

-Laser

-Linear Motion Accessory (for RMS)

-Optics Bench

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P58

B3

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 double-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 double-slit diffraction slide so that the laser beam passes through one of the double-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" and slit spacing "d" of the double-slit pattern you use in the Data section.

4.Mount the fiber optic probe in the opening of clamp on the end of the linear motion accessory of the Rotary Motion Sensor. Position the fiber optic probe so it is perpendicular to the linear motion accessory.

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 thelaser.

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 double-slit.

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 #1 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 torescale the Graph to fit the data.

1. Examine the shape of the plot of lightintensity 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 plotof the Graph to display Run #1.

4.Click the DATA Menu buttonin thetop 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.

Complete the following table:

Conclusion

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