A middle-aged man starts to wear eyeglasses with lenses of +2.0 D that allow him to read a book held as close as 25 cm. Several years later, he finds that he must hold a book no closer than 33 cm to read it clearly with the same glasses, so he gets new glasses. What is the power of the new lenses?
Answer to relevant QuestionsBifocal 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 ...A converging lens can give a maximum angular magnification of 4.0 x. What is the focal length of the lens? A compound microscope has a distance of 15 cm between lenses and an objective with a focal length of 8.0 mm. What power should the eyepiece have to give a total magnification of – 360x? A lens with a power of + 10 D is used as a simple microscope. (a) For the image of an object to be seen clearly, can the object be placed infinitely close to the lens, or is there a limit on how close it can be? Explain. ...An astronomical telescope uses an objective of power +2.00 D. If the length of the telescope is 52 cm, (a) What is the focal length of the eyepiece? (b) What is the angular magnification of the telescope?
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