Electro-Magnetic Waves III PREFLIGHT
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The following three questions refer to the material you were to read in preparation for the lesson. Questions one and three require you to write a three or four sentence response. Number two is a multiple choice question. Click in the appropriate circle.

You may change your mind as often as you wish. When you are satisfied with your responses, click the SUBMIT button at the bottom of this page. Don't submit more than once. (If you absolutely HAVE to resubmit it, put a note on the end to that effect.)


1.

Sunlight + raindrops + ice crystals = atmospheric art. Dr. Carole Strong has a webpage of all the weird and wonderful things that happen in the atmosphere when sunlight passes through atmospheric moisture. Here's short reference: http://www.treasure-troves.com/astro/AtmosphericPhenomena.html.
I'll never forget the day I was driving through northern France, which is about as exciting as Kansas, seeing the long flat fields of wheat, broken by the occasional town and spire of a Gothic church. A thunderstorm built up above the brown fields, when suddenly the most amazing rainbow appeared. It had two sets of colors, one inside the other and the first arc had a color I have never seen in a rainbow since. It was fuschia. You know the shade, a hot-pink purplish color, that was as bright as any of the other colors. (My kids will testify that they saw it too.) At first I thought maybe the French have different rainbows than America, but after teaching 113, I think there's a physics explanation. Check out the picture on page 858 and see if you can find a Physics reason.



2.

A light source is embedded inside an unknown substance.  You can click-drag both the position and the ray-angle for this source.  What is the index of refraction of the substance?  Start

1.4-1.599

1.6-1.799

1.8-1.999

2.0-2.2

3.


Why is it that when I open my eyes under water after I dive in the pool, say, to find the ladder to climb out, everything is blurry, but when I wear a swimmers goggles (you know, the ones that fit snugly over the eyes and make you look like a frog) I can see clearly? Even if I wear the goggles out of the pool, I still see clearly. What is so magic about the goggles? And do fish go blurry when they jump out of the water? (Do fish wear goggles? How about flying fish and mudskippers?).



honors extra

If the index of refraction of a light fiber core is 1.58, and the outer shell is 1.53 (see problem 83 and play with the physlet above) there is a "cone" of light for which all the light is internally reflected. From this information, explain why the telephone men do not like to bend their fiber optic cables too sharply around a corner. Calculate/Estimate the sharpest corner they can bend their cables (usually expressed as the "minimum radius of curvature").




Below is a space for your thoughts, including general comments about today's assignment (what seemed impossible, what reading didn't make sense, what we should spend class time on, what was "cool", etc.):




You may change your mind as often as you wish. When you are satisfied with your responses, click the SUBMIT button.

I received no help from anyone on this assignment.