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Convex Mirrors - Section 14C

1. The radius of Earth is 6.40 x10 3 km. The moon is about 3.84 x105 km away from Earth and has a diameter of 3475 km. The Pacific Ocean surface, which can be considered a convex mirror, forms a virtual image of the moon. What is the diameter of that image?

2. A 10 g thread of wool was produced by Julitha Barber of Australia in 1989. Its length was 553 m. Suppose Barber is standing a distance equal to the threadís length from a convex mirror. If the mirrorís radius of curvature is 1.20 x102 m, what will the magnification of the image be?

3. Among the many discoveries made with the Hubble Space Telescope are four new moons of Saturn, the largest being just about 70.0 km in diameter.  Suppose this moon is covered by a highly reflective coating, thus forming a spherical convex mirror. Another moon happens to pass by at a distance of 1.00 x102 km. What is the image distance?

4. Bob Henderson of Canada built a model railway to a scale of 1:1400.  How far from a convex mirror with a focal length of 20.0 mm should a full-size engine be placed so that the size of its virtual image is the same as that of the model engine?

6. The largest starfish ever discovered had a diameter of 1.38 m. Suppose an object of this size is placed 6.00 m in front of a convex mirror. If the image formed is just 0.900 cm in diameter (the size of the smallest starfish), what is the radius of curvature of the mirror?

7. In 1995, a functioning replica of the 1936 Toyota Model AA sedan was made in Japan. The model is a mere 4.78 mm in length. Suppose an object measuring 12.8 cm is placed in front of a convex mirror with a focal length of 64.0 cm. If the size of the image is the same as the size of the model car, how far is the image from the mirrorís surface?

8. Some New Guinea butterflies have a wingspan of about 2.80 x102 mm.  However, some butterflies which inhabit the Canary Islands have a wingspan of only 2.00 mm. Suppose a butterfly from New Guinea is placed in front a convex mirror. The image produced is the size of a but-terfly from the Canary Islands. If the image is 50.0 cm from the mirrorís surface, what is the focal length of the mirror?

 

 Answers