PART 1

 

Use the “Virtual Optics Bench” at http://webphysics.davidson.edu/physlet_resources/dav_optics/Examples/optics_bench.html to help answer these questions. Instructions are at the bottom of hte screen. All the answers will not be found on this web page.

  1. When is an image real?
  2. When is an image virtual?
  3. Where is an image placed when it is real?
  4. Where is an image placed when it is virtual?
  5. What is the minimum number of rays to draw to find an image?
  6. What is a “virtual ray?”
  7. Where on a diagram is the image located when “q” is negative?
  8. Where on a diagram is the object located when “p” is positive?
  9. What shape is a concave mirror?
  10. What is the relationship between the center, radius and focus?
  11. What is the sign of the focus when a mirror is a concave mirror?
  12. What is the sign of the focus when a mirror is a convex mirror?
  13. Which variable indicates a virtual image? How does it indicate a virtual image?
  14. Which variable indicates a real image? How does it indicate a real image?
  15. What is the minimum number of rays to draw to find an image?
  16. Mathematically, when are “p” and “q” negative?
  17. What are the four rules for drawing rays?
  18. Which type of spherical mirror only has virtual images?
  19. Which type of spherical mirror can produce an enlarged image?
  20. Which type of mirror can produce an real image?
  21. Where is an object located to produce a real image?
  22. Where is an object located to produce an inverted image in a concave mirror?


Part 2

A “characteristic” is described by

  • the magnification as being positive or negative
  • the magnification as being less than, equal to, or greater than 1.
  • p or q, as being positive or negative
  • real or virtual
  1. What are the characteristics of an image when the object is at the center of a concave mirror?
  2. What are the characteristics of an image when the object is between the center and focus of a concave mirror?
  3. What are the characteristics of an image when the object is at the focus of a concave mirror?
  4. What are the characteristics of an image when the object is at the inside of the focus of a concave mirror?
  5. What are the characteristics of EVERY image for a convex mirror?
Part 3

Do all these problems on a separate sheet of paper.

  1. The focal length of a concave mirror is 17 cm. An object is located 38 cm in front of this mirror. Where is the image located?
  2. A clown is using a concave makeup mirror to get ready for a show and is 27 cm in front of the mirror. A virtual image is formed 65 cm from the mirror. Find (a) the focal length of the mirror and (b) its magnification. (c) Is this a convex or concave mirror?
  3. The image behind a convex mirror (radius of curvature = 68 cm) is located 22 cm from the mirror. (a) Where is the object located arid (b) what is the magnification of the mirror? Determine whether the image is (c) upright or inverted and (d) larger or smaller than the object.
  4. Convex mirrors are being used to monitor the aisles in a store. The mirrors have a radius of curvature of 4.0 m. (a) What is the image distance if a customer is 15 m in front of the mirror? (b) Is the image real or virtual? (c) If a customer is 1.6 m tall, how tall is the image?
  5. A dentist's mirror is placed 1.5 cm from a tooth. The enlarged virtual image is located 4.3 cm from the mirror. (a) What kind of mirror (plane, concave, or convex) is being used? (b) Determine the focal length of the mirror. (c) What is the magnification? (d) How is the image oriented relative to the object?
  6. A small postage stamp is placed in front of a concave mirror (radius = R), such that the image distance equals the object distance. (a) In terms of R, what is the object distance? (b) What is the magnification of the mirror? (c) State whether the image is upright or inverted relative to the object.
  7. A concave shaving mirror is designed so the virtual image is twice the size of the object, when the distance between the object and the mirror is 15 cm. Determine the radius of curvature of the mirror.
  8. A shiny glass Christmas ornament in the shape of a ball is 10.0 cm in diameter. What is the magnification of an object placed 15 cm from the surface of the ball? Is the image upside-down or right-side up. Justify your answer?
  9. A makeup mirror is labeled as 5X magnification. The image is upright like the object. How far away from your eye (1.5 cm in height) does the mirror need to be held so the image is 7.5 cm tall? Answer in terms of focal lengths.
  10. When driving a car around a sharp 90° blind corner, sometimes you will see a round mirror that shows you the traffic on the other road. The image appears upright and on the other side of the mirror. What is the focal length of this mirror if the your car’s image appears to be 5 m away then your car is 7.5 meters away from the mirror?

by Tony Wayne ...(If you are a teacher, please feel free to use these resources in your teaching.)