Question

explain with at least two illustrations how we can use any two of three (special) incident ray to draw ray diagrams for obtaining the details of image formed by spherical lens.

Answer 1

  Illustrate how a flat mirror forms an image. Two rays are shown emerging from the same point, striking the mirror, and being reflected into the observer’s eye. The rays can diverge slightly, and both still get into the eye. If the rays are extrapolated backward, they seem to originate from a common point behind the mirror, locating the image. (The paths of the reflected rays into the eye are the same as if they had come directly from that point behind the mirror.) 

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