A Treatise on OpticsMacmillan, 1870 - 352 páginas |
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Términos y frases comunes
aberration achromatic angle of incidence angular aperture axis breadth bright caustic centre coincides colours concave converge convex lens cos² curve diameter direct pencil distance edge emergent equal equation excentrical eye-glass eye-piece field of view focal length foci geometrical focus glass Gregorian telescope Hence illumination image formed inches incident pencil incident ray index of refraction intersection latus rectum lenses luminous point magnifying power medium object object-glass parabola parallel rays passing pencil of parallel pencil of rays placed plane mirror plane surface point of incidence position principal focus principal plane prism radii radius ray of light rays incident reflected or refracted reflected rays reflector reflexion or refraction refracted pencil refracted rays refracting angle refracting surface refractive index shew small pencil spectrum sphere spherical reflector spherical surface subtends supposed tion V₁ αμ
Pasajes populares
Página 349 - The focal length of the object-glass of an astronomical telescope is 40 inches, and the focal lengths of four convex lenses, forming an erecting eye-piece are, respectively, f , J, f, f inches> reckoning backwards from the object-glass.
Página 330 - 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 color may be a minimum.
Página 330 - 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.
Página 294 - There are three plane reflectors, two of which are at right angles to each other, and a ray of light is incident upon the third, and reflected successively by each of them ; it is required to shew that the angle between the first incident and last reflected rays is equal to twice .the angle of incidence upon the first surface.
Página 290 - A small bead is projected with any velocity along a circular wire under the action of a force varying inversely as the fifth power of the distance from a centre of force situated in the circumference. Prove that the pressure on the wire is constant. 17. A bright spot of white light is viewed through...
Página 319 - In the simple astronomical telescope, shew that when the apertures of the two lenses are proportional to their focal lengths, the field of view (as seen by whole pencils) is a single point. If a convex lens, of the same aperture as the eye-glass, but of any given focal length, be placed in contact with the eye-glass, determine whether the field of view is thereby increased or diminished (the telescope is always supposed to be adjusted for distant objects).
Página 252 - ... be a cylindrical pencil parallel to the axis, and of the same diameter as the incident pencil.
Página 156 - Kirchhoff has shown that, if vapors of terrestrial substances come between the eye and an incandescent body, they cause groups of dark lines; and, further, that the group of dark lines produced by each...
Página 253 - An eye is placed close to the surface of a sphere of glass (fi = f ), which is silvered at the back; shew that the image which the eye sees of itself is f of the natural size.
Página 4 - ... are the distances of the focal lines from the same point of the surface, p is the radius of curvature, 7 and ft are the angles which the incident and refracted rays make with the normal at the surface. Applying this to the case of the concave grating by putting p= — 1 , we get cos...