. The principles of physics. l axis, /|^, meeting prisms of greater and ;|\ greater angles of incidence, aremore deflected than those nearer theaxis; and if the curvatures beproperly adjusted, all may be madeto converge to one point. On the other hand if the lens bethinnest at the center and graduallyincrease in thickness outward, exact-ly the opposite effect would be ex-pected. Parallel incident rays, beingbent toward the thicker part of thecomponent prisms, would becomeseparated. The general effect of all convex lenses is to cause transmittedrays to converge ; that of concave lenses, to caus
. The principles of physics. l axis, /|^, meeting prisms of greater and ;|\ greater angles of incidence, aremore deflected than those nearer theaxis; and if the curvatures beproperly adjusted, all may be madeto converge to one point. On the other hand if the lens bethinnest at the center and graduallyincrease in thickness outward, exact-ly the opposite effect would be ex-pected. Parallel incident rays, beingbent toward the thicker part of thecomponent prisms, would becomeseparated. The general effect of all convex lenses is to cause transmittedrays to converge ; that of concave lenses, to cause them to rays parallel to the principal axis of a convex lens are brought to a focus F(Fig. 268) at a point in theprincipal axis. This pointis called the principal focus, it is the focus of incidentrays parallel to the principalaxis. It may be found by holding the lens so that the raysof the sun may fall perpendicularly upon it, and then movinga sheet of paper back and forth behind it until the image of. Fig. 267.
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectphysics, bookyear1895
