Difference between revisions of "Problem Set 1"
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For each problem you identify with a single-lens, high-magnification microscope design, explain in a sentence or two and a brief sketch how multiple lenses might ameliorate the problem. | For each problem you identify with a single-lens, high-magnification microscope design, explain in a sentence or two and a brief sketch how multiple lenses might ameliorate the problem. | ||
+ | ==Question 3== | ||
+ | A plano-convex lens made of BK7<ref>http://www.escoproducts.com/html/bk-7_optical_glass.html</ref> optical glass has a focal length of 50mm in air at a wavelength of 500nm. What is the focal length of this lens when it is submerged in water? | ||
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Revision as of 16:43, 3 February 2009
Question 1
For this question, you will need to stop by the lab and make a few measurements of lenses. The whole thing should take about twenty minutes.
- Measure the focal lengths of the lenses marked A, B, and C
- Turn on the halogen lamp.
- Move the screen to produce a focused image.
- Measure the distance d1 from the imaging target to the 75mm lens, the distance d2 from the lens to the screen, and the height H of a feature on the image.
- Repeat this measurement for several values of d1
Part a
- What is your estimate of the focal lengths of lenses A, B, and C?
Part b
- What is the relationship between d1, d2, and H? Make a plot of your measurements that shows this relationship.
Question 2
In lab, you are going to build a microscope. As discussed in lecture, a single lens can act as a magnifier. You have certainly used a magnifying glass to look at something small. But microscopes that achieve very high magnifications use multiple lenses in series to make an image. This is clearly a much more expansive design. Why not use a single lens as a high-magnification microscope?
- List three potential problems with a single-lens, high-magnification microscope design. Explain the problems in few sentences and a simple sketch.
HINT: Use the information about the behavior of light in that was presented lecture. Think about the underlying assumptions of geometric optics. Under what circumstances in a real microscope design would each assumption violated? How do these violations impact the final image? If you are stuck, go back to the lecture slides and take a close, logical look at each assumption. Where does each assumption break down?
Extra credit
For each problem you identify with a single-lens, high-magnification microscope design, explain in a sentence or two and a brief sketch how multiple lenses might ameliorate the problem.
Question 3
A plano-convex lens made of BK7[1] optical glass has a focal length of 50mm in air at a wavelength of 500nm. What is the focal length of this lens when it is submerged in water?