PASCO OS-8515C Basic Optics System - Manual (Page 27)

®
M o d e l N o . O S - 8 5 1 5 C E x p e r i m e n t 9 : A p p a r e n t D e p t h
27
2. Mark the place on the paper where the two rays cross each other.
3. Position the trapezoid as shown in Figure 9.4. The “bottom” surface of the
trapezoid must be exactly at the point where the two rays cross. The crossed
rays simulate rays that originate at an object on the “bottom” of the block.
4. Trace the trapezoid and trace the rays diverging from the “top” surface.
5. Remove the trapezoid and light source. Trace the diverging rays back into
the trapezoid. The point where these rays cross (inside the trapezoid) is the
apparent position of the “bottom” of the trapezoid when viewed through the
“top”.
Analysis
1. Measure the apparent depth, d, and record it in Table 9.1.
2. Use Equation 9.1 to calculate the index of refraction and record your result
in Table 9.1.
Questions
1. Of the two methods that you used to determine d, which one is more precise?
Explain.
2. The accepted value of the index of refraction of acrylic is n = 1.49. What was the
percent difference between the accepted value and each of your two results?
t d
Convex
lens
Mirror
on edge
“bottom”
surface
“top”
surface
Figure 9.4