Manual

Basic Optics System Teacher’s Guide

Experiment 9: Apparent Depth

Typical results:

Typical ray-tracing results are represented at

50% scale in Figure TG.1. The gray regions

represent the actual light beams; the black

lines and dots represent the student’s actual

marks. Notice that this student traced along the

edges of the light beams.

The actual thickness of the trapezoid is

t = 3.175 ± 0.025 cm. Based on the accepted

value of n = 1.49, the theoretical apparent

depth is d =2.13.

Answers to questions: 1. Of the two methods, the parallax method is the more precise. Using that method,

both d and t could be measured with a precision of less than 1 mm. Using the ray-tracing method, the points at

which the rays crossed had a larger uncertainty due to the thickness of the light beams. 2. For the typical data

above, the percent differences between the accepted and experimental values of n are 0.7% for Part 1 and 5% for

Part 2.

Experiment 10: Reversibility

Typical results:

Table 1.1: Results

dtn

Part 1: Parallax method 2.12 cm 3.18 cm 1.50

Part 2: Ray-tracing method 2.23 cm 3.18 cm 1.43

Table 10.1: Data

Trial 1

Ray Incident on Flat Surface

Trial 2

Ray Incident on Curved Surface

Angle of Incidence

Angle of Refraction

Angle of Incidence

Angle of Refraction

0° 0 0 1.0

10° 7.0 7.0 7.5

20° 13.5 13.5 19.5

30° 20.0 20.0 30.0

40° 25.5 25.5 39.0

50° 31.0 31.0 49.0

60° 35.5 35.5 59.0

70° 39.5 39.5 70.0

80° 41.0 41.0 77.0

2.23 cm

Figure TG.1