Bifocal glasses are used to correct both nearsightedness and farsightedness at the same time (Fig. 25.23). If the near points in the right and left eyes are 35.0 cm and 45.0 cm, respectively, and the far point is 220 cm for both eyes, what are the powers of the lenses prescribed for the glasses? (Assume that the glasses are worn 3.00 cm from the eyes.)
Answer to relevant QuestionsUsing the small-angle approximation, compare the angular sizes of a car 1.5 m in height when viewed from distances of (a) 500 m and (b) 1050 m. When viewing an object with a magnifying glass whose focal length is 10 cm, a student positions the lens so that there is minimum eyestrain. What is the observed magnification? The far point of a certain nearsighted person is 90 cm. (a) Which type of contact lenses, (1) converging, (2) diverging, or (3) (2) diverging, or (3) bifocal, should an optometrist prescribe to enable the person to see more ...A modern microscope is equipped with a turret that has three objectives with focal lengths of 16 mm, 4.0 mm, and 1.6 mm and interchangeable eyepieces of 5.0 x and 10x. A specimen is positioned such that each objective ...You are given two objectives and two eyepieces and are instructed to make a telescope with them. The focal lengths of the objectives are 60.0 cm and 40.0 cm, and the focal lengths of the eyepieces are 0.90 cm and 0.80 cm. ...
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