Week 9 (Oct. 21 - 25)
Read: Conservation of Energy (Chap. 11) and Geometric Optics (Chap. 12)
PHY 202 Lecture: Geometric optics
PHY 202 Lecture: Geometric optics
Quiz: Monday.
Homework:
Laboratory: Reflection (Ex. 12.8) and Refraction (Ex. 12.9) labs. For the reflection lab, set up two mirrors in a V-configuration atop of a sheet of paper (see video below). Place the vertex of your V at about the middle of your sheet of paper. After setting up the mirrors, place a pin a couple of inches in front of the mirrors. Observe the image(s) of the pin that form "behind" the mirrors.
Begin with a 180 degree angle between the mirrors (they are in a straight line). In this case, a single image of the pin should appear behind the mirrors. (In subsequent experiments, you will change the angle of the mirrors so there appear exactly 3, 5, and 7 images of the pin). For each mirror configuration, try to place a pin behind the mirrors at the -apparent- location of each image. You will then do "ray tracing": draw lines on your paper that trace the path that a light ray follows from the object (the pin) to your eye to account for each image. To do this, you will need to draw a little "eye" on the paper and also lines indicating the surfaces of the mirrors. Be sure that the law of reflection is obeyed at each reflection of a ray from the mirror!
For the refraction lab, place a glass block flat in the middle of a sheet of paper. Trace the block. Then look horizontally through the block and try to set up four pins (two on your side of the glass and two on the opposite side of the glass) that appear to be in a straight line. Remove the glass block and trace the light ray that passes through all four pins. Measure the angle of of the light rays on each side of each refracting surface. Make a plot of the sine of the angle (on the air side) versus the sine of the angle (on the glass side). Obtain data points for at least four different incidence angles. Do the data points lie in a straight line? Do your data obey the law of refraction? What is the slope? What is the refractive index of your glass block? What type of glass is it made out of?
Chapter 11 (4 videos):
Chapter 12 (5 videos):
Homework:
- Combustion (Ex. 11.1)
- Reflection from mirrors in a V-configuration (Ex. 12.2)
- Bow fishing (Ex. 12.4)
- Total internal reflection (Ex. 12.5),
Laboratory: Reflection (Ex. 12.8) and Refraction (Ex. 12.9) labs. For the reflection lab, set up two mirrors in a V-configuration atop of a sheet of paper (see video below). Place the vertex of your V at about the middle of your sheet of paper. After setting up the mirrors, place a pin a couple of inches in front of the mirrors. Observe the image(s) of the pin that form "behind" the mirrors.
Begin with a 180 degree angle between the mirrors (they are in a straight line). In this case, a single image of the pin should appear behind the mirrors. (In subsequent experiments, you will change the angle of the mirrors so there appear exactly 3, 5, and 7 images of the pin). For each mirror configuration, try to place a pin behind the mirrors at the -apparent- location of each image. You will then do "ray tracing": draw lines on your paper that trace the path that a light ray follows from the object (the pin) to your eye to account for each image. To do this, you will need to draw a little "eye" on the paper and also lines indicating the surfaces of the mirrors. Be sure that the law of reflection is obeyed at each reflection of a ray from the mirror!
For the refraction lab, place a glass block flat in the middle of a sheet of paper. Trace the block. Then look horizontally through the block and try to set up four pins (two on your side of the glass and two on the opposite side of the glass) that appear to be in a straight line. Remove the glass block and trace the light ray that passes through all four pins. Measure the angle of of the light rays on each side of each refracting surface. Make a plot of the sine of the angle (on the air side) versus the sine of the angle (on the glass side). Obtain data points for at least four different incidence angles. Do the data points lie in a straight line? Do your data obey the law of refraction? What is the slope? What is the refractive index of your glass block? What type of glass is it made out of?
Chapter 11 (4 videos):
Chapter 12 (5 videos):