An object 1.7 cm high is held 3 cm from a person's cornea, and its reflected image is measured to be 0.157 cm high. Think & Prepare: 1. What kind of mirror is the cornea, convex or concave? 2. What kind of mirror causes magnification? 3. What kind of image is it? 4. What signs will the different quantities have? (a) Set-up the table for some known quantities. i) Make sure to use the correct sign for the image distances, object distances, and the focal lengths. ii) Make sure to use the correct sign for the image and object heights. Inverted object and image heights are negative. d₁ = = iii) Do NOT do any calculations for this section. h;= (b) What is the magnification? M= cm cm cm (Include the appropriate sign for an erect or inverted image) (c) Where is the image? d;= cm (include the appropriate sign) (d) Find the radius of curvature of the convex mirror formed by the cornea. cm (include the appropriate sign) R = Note that this technique is used by optometrists to measure the curvature of the cornea for contact lens fitting. The instrument used is called a keratometer, or curve measurer.

1. What is the focal length of a makeup mirror that produces a magnification of 1.51 when a person's face is 12.2 cm away? Think & Prepare: 1. What kind of mirror causes magnification? 2. What kind of image is it? 3. What signs will the different quantities have? (a) Set-up the table for some known quantities. i) Make sure to use the correct sign for the image distances, object distances, and the focal lengths. ii) Make sure to use the correct sign for the image and object heights. Inverted object and image heights are negative. iii) Do NOT do any calculations for this section. do = V cm M= (b) What is the focal length? f = cm

Which of the following statements for single optic devices are true? Choose all that apply. a. Any physicist worth their weight in garbanzo beans (not chick peas) knows that concave lenses will have a positive focal length. b. For virtual images, the image distance is positive and the object distance is negative. c. By convention, if the image height is positive then the image is upright. d. If an optic produces an image with a magnification of 0.6, then the image is diminished. e. Experiments have shown that convex mirrors can create real images. f. If an image has a magnification of -6, then the image is real.

A. Calculate the focal length of the mirror formed by the convex side of a shiny spoon that has a 1.67 cm radius of curvature. B. What is its power in diopters?