Lynde, Carleton John, b. 1872 · New York, Macmillan · leaf 274
the rays converge at some point F; and if the incidentrays are parallel, this point F is theprincipal focus of the lens. In Fig. 188 is shown a concave lensmade up of sections of prisms. In thiscase the thinner ends of the sectionspoint towards the center. A ray oflight falling on one of these… … FIG. 188. — A concave lens, 260 PHYSICS OF THE HOUSEHOLD Images. — Images are of two kinds, real and virtual.An image is real when the rays which produce it actuallypass through the image. An image is virtual when the rayswhich produce it only appear to pass through the image. A realimage can be…
Physics · Home Economics
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