Conceptual Questions:
1. Be prepared to draw ray-trace diagrams to locate images for different kinds of mirrors and lenses.
2. Give examples of both real and virtual images. What distinguishes each?
3. Which of the following best describes the image for a thin convex lens that forms whenever the object is at a distance less than one focal length from the lens?
a. It is inverted, enlarged and real.
b. It is upright, enlarged and virtual.
c. It is upright, diminished and virtual.
d. It is inverted, diminished and real.
4. Which of the following best describes the image in a plane mirror?
a. It is virtual, inverted and magnification greater than one.
b. It is real, inverted and magnification less than one.
c. It is virtual, upright and magnification equal to one.
d. It is real, upright and magnification equal to one.
5. Which of the following lens aberrations:
a. results the index of refraction of glass varying with wavelength?
b. results from the radius of curvature of the surface?
c. occurs only for off-axis images?
d. results from lens assymetries?
i.e. match letters above with answers below
a. spherical
b. coma
c. chromatic
d. astigmatism
6. What kind of lens is required to correct nearsightedness?
Numerical Problems: answers link to a help page.
1. You stand one meter away from a plane mirror. How far is it from you to your image?
2. An object is at a distance of 30 cm from a thin convex lens, along its axis. The lens has a focal length of 10 cm. What are the values, respectively, of the image distance and magnification?
3. A projector lens is needed to form an image on a screen 10 times the size of its corresponding object. The screen is located 8 m from the lens. What is the required focal length of the lens?
4. What is the image location of an object 1 m in front of a converging lens of focal length 20 cm?
5. A magnifying glass has a convex lens of focal length 15 cm. At what distance from a postage stamp should you hold this lens to get a magnification of +2?