Teacher’s guide – PASCO OS-8533A POLARIZATION ANALYZER User Manual

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012-09200A

Polarization Analyzer

Teacher’s Guide

Data Analysis

Sample Data

In the data analysis section, the curve fit for the polynomial function is second degree. This indicates that the light
intensity varies as the square of the cosine of

. This is confirmed by the curve fit for the linear function when

light intensity is compared to the square of the cosine.

Answers to Questions

1. What is the shape of the graph of the intensity versus the

angle?

Answers will vary. The shape of the graph of the intensity
vs. the angle is approximately sinusoidal.

2. What is the shape of the graph of the intensity versus the

cosine of the angle?

The shape of the graph of the intensity vs. the cosine of the
angle is a parabola.

3. What is the shape of the graph of the intensity versus the

square of the cosine of the angle?

The shape of the graph of the intensity vs. the square of
the cosine of the angle is a straight line.

4. Theoretically, what percentage of incident plane polarized

light would be transmitted through three polarizers which
each have their axes rotated 17 degrees from each other?
Assume ideal polarizers and assume that the first
polarizer’s axis is 17 degrees from the axis of the second
polarizer.

Assuming ideal filters, the intensity passing through the
first filter would be 50% of the initial intensity. The
intensity after the second filter would be reduced by
cos

(17½) = 0.9145 of the intensity passing through the

first filter. Thus the intensity after passing through two
filters would be 45.73%. The light passing through the
third filter would be reduced by another 0.9145. So the
three polarizers reduces the light intensity to
50%*(0.9145)

= 41.82%.

5. From your graph, determine the answer to Question #4

for the real polarizers.

Answers will vary. From the example, we see that the
intensity at 17½ is 98%, so the final intensity should be
(.98)

= 96% of the intensity that passes through the first

filter. Using the sample data we see that only 33% passes
through the first filter, thus the intensity of the light that
passes through three filters is 96% of 33% or 31.68%.

Sample Data: Light Intensity versus Angle

Sample Data: Light Intensity vs. Cosine Angle

Sample Data: Light Intensity vs. Cosine

Angle