Index of Refraction

(this experiment is to be used with the Waves lab from SPECS)

The Index of Refraction is the ratio of the speed of light in a vacuum to the speed of light in a medium.

n = speed of light in a vacum/speed of light in the medium = c/v

Remember as light travels from one medium to another its wavelength changes, NOT its frequency.


To see the effect changing the index of refraction has on waves.

Words you should know

amplitude, constructive interference, destructive interference, diffraction, frequency, fundamental frequency, index of refraction, phase angle, and superposition.

glossary of terms

Step 1: Create two objects. Change the Index of Refraction to 50 for one of the objects.

Step 2: Place the objects so that they are above one another. One in the top half and one in the bottom half of the screen. Run the program and record your observations. Remember you can move the graph pointer tool to change the location you are observing. You can also make a copy of the graph to help you compare.

Compare the behavior of the waves around each object.

Step 3: What could account for the similarities and differences you see? Don't just say that the Indexes of Refraction are different, what does that mean?

 Step 4: Change the type of objects and compare them with your first run. Remember to keep one objects index of refraction at 0 and the other at 50.

 How does changing the shape of the objects change the interaction? Record your observations?

 Step 5: Now vary the index of refraction to see what effect this has on your wave.

What conclusions or summary statement can you make about the index of refraction and its effect on waves?

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