Physics: Principles with Applications (7th Edition)

Published by Pearson
ISBN 10: 0-32162-592-7
ISBN 13: 978-0-32162-592-2

Chapter 25 - Optical Instruments - Search and Learn - Page 743: 2

Answer

a. False. b. True. c. False. d. False.

Work Step by Step

a. False. This is explained on page 741. Contact lenses are placed directly on the eye. In contrast, the lenses in glasses are about 2 cm in front of the eyes. An image that is, say, required to be 30 cm away from the eye will be 30 cm away from a contact lens but only 28 cm away from the lens in a pair of glasses. The prescription for contacts lenses differs slightly from the prescription for glasses, even for the same person. b. True. This is the definition of the term “farsighted”: the near point is large, and the person cannot see nearby objects very clearly. c. False. Nearsighted people can see nearby objects clearly. Their issue is that the eye’s far point is relatively short, so distant objects are blurry. d. False. To correct astigmatism, a nonspherical lens is required. The cornea is asymmetric, so a spherical lens won’t do the trick.
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