# Physics..4slp

For this module, you will investigate the phenomenon of refraction. The simulation allows you to experiment with changes in the angles of incidence and combinations of materials. Do the following:

Click on the following link to access the simulation (number 5 on the list of required readings and resources: see the Background Information for this module).

Fendt, W. (1997). Refraction of light (simulation). Retrieved on March 1, 2008, from http://www.walter-fendt.de/ph14e/refraction.htm

The first part of the simulation is a series of measurements designed to demonstrate the validity of Snell’s Law. The light ray passes from medium 1, which has an index of refraction n1, into medium 2, with an index of refraction of n2. The angle of incidence is Î¸1, the angle of refraction Î¸2. Complete the table below. (The first line has been completed for you.) Explain in detail how your results demonstrate the validity of Snell’s Law.

 Medium 1 n1 Medium 2 n2 target q1 actual q1 n1sinq1 q2 n2sinq2 Vacuum 1.00 Quartz 1.46 30 30.3 0.50 20.2 0.50 Vacuum Quartz 60 Vacuum Quartz 90 Vacuum SF2 30 Vacuum SF2 60 Vacuum SF2 90 Vacuum Diamond 30 Vacuum Diamond 60 Vacuum Diamond 90 BK7 SF2 30 BK7 SF2 60 BK7 SF2 90

The second part of the simulation examines total internal reflection. If you’ve ever snorkeled or SCUBA-dived, you’ve noticed this. If the water is smooth, and you look nearly straight up, you can see objects above the water. If you look beyond a certain angle, you see only water. That “certain angle” in the critical angle, Î¸crit.

In the simulation, adjust the angle of incidence until the angle of refraction is just equal to 90 degrees. Record the data in the table below. Explain your results in terms of Snell’s Law.

 Medium 1 n1 Medium 2 n2 qcrit sinqcrit n2/n1` Water 1.33 Air 1.00 49.1 0.76 0.75 SF2 1.33 Diamond 1.65 Diamond 1.00