Elements of natural philosophy (Volume 2-3) (1850)
Bartlett, W. H. C. (William Holms Chambers), 1804-1893 · New York : Barnes · leaf 214
ELEMENTS OF OPTICS. 205 tween the lens and the principal focus, it will, after Give virtual focLdeviation, proceed from some other point in front, and thefocus will be virtual. Fo] 1 1 _ - j? 1 f = 0, or/ = oo Fis. 29. … Real radiant atprincipal focus. F„ f That is, the vergencyof the deviated rayswill be zero, and aspherical wave pro-ceeding from the prin-cipal focus will be con-verted, by deviation,into a plane wave which can only be concentrated into a point at an infinitedistance. If the rays be received by the…
Mechanics · Acoustics · Optics
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