The applet shows a right traveling light wave (shown in blue) incident on a region comprised of unknown index of refraction embedded in air.  The left traveling wave (shown in red) above it represents the sum of all reflections of the incident wave at the boundaries.  Notice that the amplitude of the incident wave varies with the medium in order to conserve energy.

Observe how the intensity of light transmitted through the medium changes by using the slider to change the thickness of the substance.  Note: because the data points are connected, you must move the slider slowly to obtain a smooth curve.  Restart

a) Why are there numerous transmission peaks?

b) What is the index of refraction of the material?

Physlet Problem by Melissa Dancy and Wolfgang Christian