Unit 4 Assignment

Unit 4 Assignment

For this lab assignment, you will use a simulation on the ActivPhysics section of the Physics Place website. Select activity 15.2 Total Internal Reflection, and run Applet 1. This simulation will help you understand reflection, refraction, and total internal reflection. Please see the figure below for directions on how to access the simulation.


The simulation illustrates an experiment where a ray of light is incident in one medium and is refracted into a second medium. You will set the angle of incidence to various values and observe the effect it has on the angle of refraction. Please see the figure below for directions on how to run the simulation and collect data for your report.


For your lab report, please address the following questions:

1. What is the objective of this assignment?

2. Explain total internal reflection. Under what conditions does it take place?

3. Start Applet 1. Select incident ray in Larger n region and set nupper equal to 1.00. This is a case where a light ray goes from a higher index medium into a lower index medium.

4. In this step, you will change the values of the angle of incidence θ1 and record the values of the angle of refraction θ2. In each of the three cases below, record data until the angle θ2 reaches 90 degrees (after 90 degrees there is no more refraction).

a. Set nlower equal to 1.10. Set the angle of incidence θ1 to 10, 20, 30, 40, 46, 50, 56, 60, and 65 degrees. Each time you set the value of θ1, record the value of the angle of refraction θ2.

b. Set nlower equal to 1.20. Set the angle of incidence θ1 to 10, 20, 30, 40, 46, 50, 56, 60, and 65 degrees. Each time you set the value of θ1, record the value of the angle of refraction θ2.

c. Set nlower equal to 1.40. Set the angle of incidence θ1 to 10, 20, 30, 40, 46, 50, 56, 60, and 65 degrees. Each time you set the value of θ1, record the value of the angle of refraction θ2.

5. On the same spreadsheet, input the data from question 4 as follows:
The values of θ1 in the first column. The values of θ2 for nlower = 1.10 in the second column. The values of θ2 for nlower = 1.20 in the third column. The values of θ2 for nlower = 1.40 in the fourth column. Plot the values of θ2 vs. θ1. You should have three curves on your plot.


6. What type of curves do you get? How does θ2 vary as θ1 increases?
Can you determine the critical angle from the curves?

7. Write a conclusion.