Test Prep for AP® Courses

9.1 Physics of the Eye


A tree that is 3 m tall is viewed from a distance of 25 m. If the cornea-to-retina distance of an ideal eye is 2 cm, how tall is the image of the tree on the observer’s retina?

  1. 0.24 cm
  2. 0.5 cm
  3. 0.5 m
  4. 0.08 cm

Often people with lens-to-retina distances smaller than 2 cm purchase glasses to place in front of their eyes.

  1. Explain why people with lens-to-retina distances smaller than 2 cm need glasses.
  2. Explain whether the glasses should be composed of converging or diverging lenses.
  3. Draw a ray diagram demonstrating the ability to see with and without the glasses.

9.2 Vision Correction


Which of the following types of light have a wavelength greater than that of visible light?

    1. Gamma rays
    2. Infrared
    3. Radio
    4. Ultraviolet
  1. I, II, and III
  2. I and IV only
  3. II and III only
  4. III only

In LASIK surgery, a coherent UV light of 193 nm is focused on the corneal tissue.

  1. Explain the importance of using light that is all the same wavelength.
  2. Explain why UV light is more effective than infrared light at evaporating the corneal tissue.

9.3 Color and Color Vision


A student sees a piece of paper sitting on a table. Which of the following would not result in the student observing the paper as yellow?

  1. Yellow light shines on a black paper.
  2. White light shines on a yellow paper.
  3. Yellow light shines on a white paper.
  4. Red and green lights shine on a white paper.

A white light is projected onto a tablecloth. Using the light reflecting off the tablecloth, an observer determines that the color of the tablecloth is blue.

  1. Using the wave model of light, explain how the observer is capable of making this judgment.
  2. Describe how using the particle model of light limits our explanation of the observer’s judgment.

9.4 Microscopes


Which of the following correctly describes the image created by a microscope?

  1. The image is real, inverted, and magnified.
  2. The image is virtual, inverted, and magnified.
  3. The image is real, upright, and magnified.
  4. The image is virtual, upright, and magnified.

Use the diagram shown below to answer the following questions.

The image shows a horizontal dashed line. A small upright arrow stands on the line. A medium gray ellipse is centered on the line a short distance away from the arrow. A large gray ellipse is centered on the line farther away from the arrow.
Figure 9.31

Draw two rays leaving the arrow shown to the left of both lenses. Use ray tracing to draw the images created by the objective and eyepiece lenses. Label the images as io and ie.

9.5 Telescopes


Which of the following is an advantage to using a concave mirror in the construction of a telescope?

  1. The telescope can gather more light than a telescope using lenses.
  2. The telescope does not suffer from chromatic aberration.
  3. The telescope can provide greater magnification than a telescope using lenses.
  1. I and III only
  2. II only
  3. I and II only
  4. I, II, and III

A spherical mirror is used to construct a telescope.

  1. Using the picture below, draw two rays incident on the object mirror and continue their path through the eye lens.
    The image shows three shapes. At the lower left, there is an ellipse with horizontal axis. Above the ellipse is a small, tilted plane. On the right side is a vertical, curved shape (one side concave and one convex).
    Figure 9.32
  2. The plane mirror is replaced with a concave lens. Using the picture below, draw the path of two incident rays.
    The image shows two shapes. On the left is a vertical shape with concave sides. On the right is a vertical, curved shape (one side concave and one convex).
    Figure 9.33
  3. Using the concave lens setup, describe the final image created by the concave lens.

Two concave lenses, of focal lengths 500 mm and 20 mm, are used in the construction of a telescope. Given any potential arrangement, what is the largest possible magnification the telescope may have?

  1. 100×
  2. 10,000×
  3. 25×