Laboratory

In this laboratory you will perform the following simple experiments with prisms and lenses:

• Determine the index of refraction of a prism material.
• Demonstrate total internal reflection (TIR) with right-angle prisms and show how to use the prisms to produce (a) 90° bending, (b) retroreflection, and (c) “periscope-type” bending.
• Determine the index of refraction of a thin-lens material.
• Determine the focal lengths of convex and concave lenses.

Equipment List

The following equipment is needed to complete this laboratory:

1 equilateral prisma (25-mm faces by 25 mm long works well)
2 45°-45°-90° prismsa (25-mm legs, 35-mm hypotenuse, 25 mm thick)
2 diode laser pointersb (5 mW or less)
1 spherometerb
1 double-convex lensa (75-mm diameter by 150-mm focal length)
1 double-concave lensa (75-mm diameter by 150-mm focal length)
1 protractor
1 white cardboard screen
Index cards, white paper sheet, ( 8½" × 11" and 11" × 17"), masking tape, and ruler
Procedure

A.Index of Refraction of a Prism Material
1. Arrange the laser pointer, equilateral prism, and white cardboard screen on a flat tabletop as shown in Figure L-1. Center the prism over a sheet of white paper. Fasten down the white paper, cardboard screen, and laser with tape.