User's Manual

Brewster’s Angle Accessory Model No. OS-8170A

Further Investigation

I. Intensity of reflected light (without polarizer)

Note: This experiment uses the same setup except the Analyzing Polarizer is removed and you

do not need the second optics bench, aperture bracket, and High Sensitivity Light Sensor.

1. Reflect the laser beam off the outside plane side of the “D” lens.

2. Make a graph of Light Intensity versus Angle where Angle is a calculation:

Angle = (180-abs(x)/15)/2,

where x is the Angular Position. (For instructions on creating equations in DataStudio, see

Appendix A of this manual.)

3. Repeat Step 1 of the procedure for the Brewster's Angle experiment. Then do Step 2, except

this time, sweep the Light Sensor on the Spectrophotometer Arm through the reflected laser

beam. The result is an intensity peak. Do not stop recording data. Use a Smart Cursor to

measure the angle at maximum intensity and the magnitude of the maximum intensity. It is

useful to have the graph set on a sliding scale, but if the Smart Cursor is used, you will need

to click on “show live data” in the pull down menu to resume the sliding scale.

4. Repeat the procedure for angles in increments of 5 degrees.

5. Under the "Experiment" pull-down menu in DataStudio, click “New Empty Data Table”.

Enter the data, and make a graph of Light Intensity versus Angle.

6. Repeat the experiment with the laser beam entering the curved side of the lens and reflecting

off the inside of the plane side of the lens. This will give the critical angle for total internal

reflection.

II. Intensity of Transmitted Light

This experiment uses the same setup as part I “Reflected Intensity,” but the slits should both be

set on #3.

1. The computer can measure the refracted angle, but not the incident angle. You must read the

markings on Brewster's base and enter them manually.

2. Arrange the curved part of the lens so it is towards the laser. Set the Pivot Plates base angle to

10 degrees. Sweep the Light Sensor through the reflected laser beam. The result is an

intensity peak. Do not stop recording data. Use a Smart Cursor to measure the angle to

maximum intensity and the magnitude of the maximum intensity

3. Repeat the procedure for angles in increments of 10 degrees.