Plastic index of refraction

Experiment

1. Place the solid plastic semi-circle on paper and shine the laser through the plastic flat surface close to the center of that flat side. A large incidence angle (large to the normal) yields the best results.

2. Now record on the paper the laser beam positions and the semi-circle position. Include also the reflected beam  as well as the beam that passes through the plastic.

Analysis

• On the paper, sketch/label in details such as incident, reflected and refracted beams. Outline/label the plastic semi-circle. Make it obvious on the paper what was happening.
• Measure the angles of refraction with a protractor on the paper sketch
• Determine the index of refraction for the plastic.

Questions

• How exact can you measure angles in this experiment.
• How exact is your sketch in noting beam positions. Relate this to an uncertainty in angular measurements.