414 Week 12: Lenses and Mirrors
Homework for Week 12
Problem 1.Physics Concepts
Make this week’s physics concepts summary as you work all of the problems in this week’s
assignment. Be sure to cross-reference each concept in the summary to the problem(s)
they were key to. Do the work carefully enough that you can (after it has been handed
in and graded) punch it and add it to a three ring binder for review andstudy come
finals!Problem 2.Derive the equation
1
s+^1
s′=^1
f=^2
r
for a spherical concave mirror as seen in class. Remember, this involves drawing a
picture of an object that is a point on the axis of the mirror and the rays that local its
point-image, then doing some work with triangles and the small angle approximation.Problem 3.Produce ray diagrams for both lenses and mirrors for all permutations of the following
data:f= 10 cm.f=−10 cm.s= 10, 20 , 40 ,60 cm. In all cases locate the image (give
s′), find the magnificationm, and indicate whether the image is erect or virtual.Problem 4.Prove that thelateral magnificationor an object is:ml=∆s′
∆s=
s′^2
s^2(1008)
I’d “suggest” that you think about your friend, thebinomial expansion, when solving
this problem. Is the image “inverted”?Problem 5.The human eye is the primary optical instrument. Draw a normal eye, a nearsighted
eye, and a farsighted eye, showing the location of the relaxed-eyefocal length in all three
cases. Draw them a second time with the appropriate corrective lenses, showing with
simple rays how they work to fix the problem(s).