PHYS 1062 Lecture Notes - Lecture 10: Near-Sightedness, Corrective Lens, Optical Power
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Example: a microscope has an objective lens of 10 mm focal length and an eyepiece of 25 mm focal length. -> human eye: relaxed lens; tensed lens; angular size. -> owl eye; bird eye; fly eye; mosquito eye. -> defeats of eye: (a) nearsightedness (myopia): only can focus on nearby objects; Corrective lens (diverging lens) :images of distant objects are focused in front of the retina. Example: what is the focal length of the corrective lenses for a myopic individual whose uncorrected far point is 20 cm? (b) farsightedness (hyperopia): can"t focus on nearby objects; Corrective lens (converging lens) : images of nearby objects are focused behind the retina. Example: a certain farsighted person has a minimum distance of distinct vision of 150 cm. He wishes to read type at a distance of 25 cm. Challenging problem: (will not be discussed and will not be included in the exam)