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  2. Alhazen's problem - Wikipedia

    en.wikipedia.org/wiki/Alhazen's_problem

    The problem comprises drawing lines from two points, meeting at a third point on the circumference of a circle and making equal angles with the normal at that point (specular reflection). Thus, its main application in optics is to "Find the point on a spherical convex mirror at which a ray of light coming from a given point must strike in order ...

  3. Engineering drawing abbreviations and symbols - Wikipedia

    en.wikipedia.org/wiki/Engineering_drawing...

    All information missing from the drawing is to be pulled from a 3D model of the part or assembly. LH: left-hand: Referring to handedness, such as the helix handedness of screw threads or the mirror-image handedness of a symmetrical pair of parts. LM or L/M: list of materials: Also called a bill of materials (BoM, BOM).

  4. Geometrical optics - Wikipedia

    en.wikipedia.org/wiki/Geometrical_optics

    For mirrors with parabolic surfaces, parallel rays incident on the mirror produce reflected rays that converge at a common focus. Other curved surfaces may also focus light, but with aberrations due to the diverging shape causing the focus to be smeared out in space. In particular, spherical mirrors exhibit spherical aberration. Curved mirrors ...

  5. Optics - Wikipedia

    en.wikipedia.org/wiki/Optics

    Euclid stated the principle of shortest trajectory of light, and considered multiple reflections on flat and spherical mirrors. Ptolemy, in his treatise Optics, held an extramission-intromission theory of vision: the rays (or flux) from the eye formed a cone, the vertex being within the eye, and the base defining the visual field. The rays were ...

  6. Foucault's measurements of the speed of light - Wikipedia

    en.wikipedia.org/wiki/Foucault's_measurements_of...

    The light reflected back from the spherical mirrors is diverted by beam splitter g towards an eyepiece O. If mirror m is stationary, both images of the slit reflected by M and M' reform at position α. If mirror m is rapidly rotating, light reflected from M forms an image of the slit at α' while light reflected from M' forms an image of the ...

  7. Method of image charges - Wikipedia

    en.wikipedia.org/wiki/Method_of_image_charges

    The method of image charges (also known as the method of images and method of mirror charges) is a basic problem-solving tool in electrostatics.The name originates from the replacement of certain elements in the original layout with fictitious charges, which replicates the boundary conditions of the problem (see Dirichlet boundary conditions or Neumann boundary conditions).

  8. Photometry (optics) - Wikipedia

    en.wikipedia.org/wiki/Photometry_(optics)

    Watts can also be a direct measure of output. In a radiometric sense, an incandescent light bulb is about 80% efficient: 20% of the energy is lost (e.g. by conduction through the lamp base). The remainder is emitted as radiation, mostly in the infrared. Thus, a 60 watt light bulb emits a total radiant flux of about 45 watts.

  9. Parabolic reflector - Wikipedia

    en.wikipedia.org/wiki/Parabolic_reflector

    An oblique projection of a focus-balanced parabolic reflector. It is sometimes useful if the centre of mass of a reflector dish coincides with its focus.This allows it to be easily turned so it can be aimed at a moving source of light, such as the Sun in the sky, while its focus, where the target is located, is stationary.