Lynde, Carleton John, b. 1872, Gilbert, Alfred C. (Alfred Carlton), 1884-1961 · New Haven, Conn. : A.C. Gilbert Co. · leaf 114
Spectacles are lenses, and opticians measure the power of thespectacle lenses as follows: If the lens has a focal length of1 meter it is said to have a power of 1 diopter; if it has a focallength of 1-2, 1-3, or 1-10 meter it is said to have a power of 2, 3,or 10 diopters; and so on. That is, the… … Fig. 169. Conjugate foci each of these divisions is 1 centimeter, and 100 of these makea meter. Experiment No. 109. Power of your lenses. Measure incentimeters the focal length of the 8-inch lens. Do you find 100 it to be 20 cms. ? Is the power of the lens then = 5 diopters ? 20 Repeat with the…
Light · Scientific recreations
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