Images II PREFLIGHT

Please type your (first) name: Please type your LAST NAME and LAST FOUR SS# digits: IN:

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.

Dr. Don Gregory (UAH Physics) has a contract with NASA to make reflecting fresnel mirrors that can be used in space to focus sunlight onto a "heat engine" that then generates thrust. This rocket propulsion concept is called "solar thermal" to differentiate it from solar panels and plasma acceleration, which is called "solar electric". http://www.thiokol.com/SolarThe.htm Why does NASA want mirrors and not lenses? Can you think of at least 2 reasons based on this chapter.




2.

The principal rays are drawn as you click-drag the top of the arrow shaped object in the animation.  Which statement below is true?  Start

The magnification changes sign when the tip of the arrow is dragged below the principal axis.

Virtual images always invert the object.

Light rays leaving the tip of the arrow always pass through the image.

The image of an object that is not on the principal axis can never overlap the object.


3.


If you knew that the human eye had a lens that was about 3 times larger in diameter than it was thick, and was made out of collagen, estimate the focal length if it were in air, and if it were in water.




honors extra


Mythology tells us that the Sphinx would always ask this riddle, and if unhappy with the answer, would eat the answerer: what walks on 4 legs in the morning, 2 legs at noon, and 3 legs in the evening? The modern equivalent might be my question for the optician: Why do I need glasses at age 12, bifocals at age 50 and trifocals at age 65? (What does aging do to my eyes?).





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.