Physics 102
Ray Tracing
Elizabeth Silva and Maria Zavala
April 5,2006
Abstract:
In this experiment we will see how light travels through space, various lenses, and mirrors. We will follow the progress of a series of light beams as they encounter various optical devices by tracing all the incident and reflected/refracted rays; as well as all optical devices.
Data:
Plane Mirror:Angle of incidence (degrees) / 40.0
Angel of reflection (degrees) / 41.5
Convex Mirror:
Distance from focal point to mirror (cm) / 2.45
Concave mirror:
Diameter (cm) / 10.80
Focal point (cm) / 2.70
Convex lens:
Focal point (cm) / 9.10
Distance from tangent point to where perpendiculars cross (cm) / 11.90
Concave lens:
Focal point (cm) / 14.30
Plano-convex lens:
Angle of incidence (degrees) / 44.5
Angel of reflection (degrees) / 90.0
Calculations:
Convex Mirror:
To calculate the center of curvature-
Concave Mirror:
To calculate the radius of curvature of a concave mirror-
To calculate the diameter of the concave mirror you use the radius of curvature. The diameter is two times the radius.
Convex Lens:
To find the index of refraction use the lensmakers’ equation; where n is the index of refraction, f is the focal point, Ri is the point at which all the tangent lines cross on one side of the lens, and Rr is the point at which all the tangent lines cross on the other side of the lens.
Results:
Flat mirror:Angle of incidence (degrees) / 40.0
Angle of refraction (degrees) / 41.5
Convex mirror:
Focal point (cm) / 2.45
Center of curvature (cm) / 4.90
Concave mirror:
Focal point (cm) / 2.70
Radius of curvature (cm) / 5.40
Diameter for the concave mirror (cm) / 10.80
Convex lens:
Ri (cm) / 11.90
Rr (cm) / 10.10
Index of refraction / 1.60
Concave lens:
Focal point (cm) / 14.30
Plano-convex lens:
Critical angle (degrees) / 41.5
Percent Difference:
Percent Difference:Flat Mirror / 3.70%
Convex Lens / 16.40%
Questions:
1. List two uses for each concave and convex mirrors.
Concave mirror- telescopes and solar powered gadgets
Convex mirror- security mirror in back of liquor stores and car passenger side mirrors
2. Show in a diagram how the effects of a convex lens can be negated by a concave lens of the same curvature.
3. Predict what you would see if you were to look up at the surface from the bottom of a swimming pool (with a divers mask and sufficient air).
You would see total internal reflection of whatever is inside the pool.
Conclusion:
This experiment showed the effects of light traveling through various lenses and mirrors. The angle of refraction was not always the same as the angle of incidence. This was evident with the convex lens, there was a 16.40% difference in the angles. This may have been because of the inaccuracy of the drawings. The flat mirror showed only a 3.70% difference between the two angles, but they should have been equal. The initial set up of the experiment may have been the cause of a difference. The initial rays should have been set up as parallel, the equipment may have been set up inaccurately.
88/100