PASCO OS-8500 INTRODUCTORY OPTICS SYSTEM - Manual (Page 20)

Introductory Optics System 012-02744K
®
14
Table 4.1 Data
Angle of: Incidence Refraction
1
Refraction
2
0°
10°
20°
30°
40°
50°
60°
70°
80°
90°
Without disturbing the alignment of the Lens, rotate
the Ray Table and observe the refracted ray for
various angles of incidence.
➀ Is the ray bent when it passes into the lens perpen-
dicular to the flat surface of the lens?
_______________________________________
_______________________________________.
➁ Is the ray bent when it passes out of the lens
perpendicular to the curved surface of the lens?
_______________________________________
_______________________________________.
By rotating the Ray Table, set the angle of inci-
dence to each of the settings shown in Table 4.1 on
the following page. For each angle of incidence,
measure the angle of refraction (Refraction
1
).
Repeat the measurement with the incident ray
striking from the opposite side of the normal (Re-
fraction
2
).
➂ Are your results for the two sets of measurements
the same? If not, to what do you attribute the
differences?
___________________________________________________________________
_______________________________________________________________________.
On a separate sheet of paper, construct a graph with sin(angle of refraction) on the x-axis
and sin(angle of incidence) on the y-axis. Draw the best fit straight line for each of your two
sets of data.
➃ Is your graph consistent with the Law of Refraction? Explain.
_____________________________________________________________________________________________.
➄ Measure the slope of your best fit lines. Take the average of your results to determine the
index of refraction for acrylic (assume that the index of refraction for air is equal to 1.0).
n = ________________________________________.
Additional Questions
➀ In performing the experiment, what difficulties did you encounter in measuring the angle of
refraction for large angles of incidence?
➁ Was all the light of the ray refracted? Was some reflected? How might you have used the
Law of Reflection to test the alignment of the Cylindrical Lens?
➂ How does averaging the results of measurements taken with the incident ray striking from
either side of the normal improve the accuracy of the results?