A Treatise on Optics |
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Common terms and phrases
aberration achromatism angle of incidence bright caustic centre circle of least coincides colours concave conical surfaces converge convex lens cos² curve cuts the axis diameter direct pencil distance emergence equal equation excentrical eye-glass eye-piece fixed lines focal length geometrical focus glass Hence illumination inches incident directly incident pencil index of refraction lenses luminous point magnifying power medium object object-glass parallel rays passing pencil is incident pencil of light pencil of parallel pencil of rays pencil whose axis perpendicular plane mirror plane surface point of incidence position primary plane principal focus principal plane prism radii radius rays incident reflected or refracted reflexion or refraction refracted pencil refracted rays refracting angle refracting surface refractive index retina shew sin² small pencil spectrum sphere spherical reflector spherical surface supposed telescope thin lens V₁ v₂ αμ
Popular passages
Page 347 - Find the radius of the arc which represents any other parallel. 19. The Sun's light is refracted through a prism, the edge of which is vertical. Find the position of the refracting surfaces in order that for a given altitude of the Sun the deviation of the rays of a given colour may be a minimum.
Page 340 - The lenses of a common astronomical telescope, whose magnifying power is 16, and length from object-glass to eye-glass 8| inches, are arranged as a microscope to view an object placed f of an inch from the object-glass; find the magnifying power, the least distance of distinct vision being taken to be 8 inches.
Page 346 - A plane mirror, moveable about an axis in its own plane parallel to the axis of the Earth, revolves from east to west with half the Sun's apparent diurnal motion.