# Light slp

SCI202 – Applied Physics II
##### Module 4 – SLP
###### Light

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

Write up your results, and upload them to CourseNet.

## SLP Assignment Expectations:

In general, SLPs are expected to possess the attributes of precision, clarity, breadth, depth, and applicability.  Not all of these are relevant to the answer to every problem in the SLP.  When it is relevant, the evidence for each attribute is as follows.

• Precision:  Numerical answers are calculated correctly, to the correct number of significant figures.  When a simulation is used, the results are accurate.
• Clarity:  The problem is restated in its simplest form.  Relevant variables are identified.  Formulas are algebraically rearranged, as necessary.  All the mathematical steps are shown, in logical order.
• Breadth:  Where discussion is required, the question is placed in context.  Alternatives are considered.
• Depth:  Where discussion is required, the question is examined in detail.  No relevant aspect of the question is omitted.
• Applicability:  When required, the practical importance of the principle or phenomenon is accurately described.