{"id":1191,"date":"2021-12-09T04:01:48","date_gmt":"2021-12-09T04:01:48","guid":{"rendered":"https:\/\/physics.educour.in\/isc\/?p=1191"},"modified":"2022-01-07T07:36:20","modified_gmt":"2022-01-07T07:36:20","slug":"geometrical-optics-introduction","status":"publish","type":"post","link":"https:\/\/physics.educour.in\/isc-physics\/geometrical-optics-introduction\/","title":{"rendered":"Geometrical Optics (Introduction)"},"content":{"rendered":"\t\t
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In geometrical optics we analyze the formation of images by assuming the light to travel in a straight line path or rays. For this reason geometrical optics is also known as ray optics.<\/p>

Ray of Light:<\/strong><\/h4>

A ray of light gives the direction of propagation of light. When light meets a surface, which separates the two media, reflection and refraction take place. An image or an array of images may be formed due to this.<\/p>

Beam of light:<\/strong><\/h4>

A beam of light is a bunch of light rays. It may be convergent, divergent or parallel.<\/p>

  1. A convergent beam is that in which the rays are directed towards a point.<\/li>
  2. A divergent beam is that in which the light rays are directed away from a point.<\/li>
  3. In a parallel beam of light all the ray are parallel to each other.<\/li><\/ol>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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    Object and image<\/strong><\/h4>

    The point of intersection of the incident rays is called object<\/strong> and the point of intersection of the corresponding reflected \/ refracted rays is called image<\/strong>.<\/p>

    Real Object:<\/strong><\/h5>

    If the incident rays diverge from a point, it is called a real object.<\/p>

    Virtual Object:<\/strong><\/h5>

    If the incident rays converge and appear to intersect at point behind the optical device (mirror, lens etc.), the point is virtual object.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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    Real Image:<\/strong>\u00a0\u00a0\u00a0\u00a0\u00a0<\/h5>

    If the reflected or refracted rays actually intersect at point, the point is called real image.<\/p>

    Virtual image<\/strong>:\u00a0\u00a0<\/h5>

    If the reflected or refracted rays do not actually intersect at point, but appear to come from a point, the point is called a virtual image.<\/p>

    \u00a0<\/p>

    Note:<\/strong><\/h5>

    we cannot distinguish between real and virtual image just by observing it. Only difference is that, a real image can be taken on screen, where as a virtual cannot be formed on a screen.<\/p>

    \u00a0<\/p>

    Note:<\/strong><\/h5>

    In most of the problems in this section our primary goal is to locate the final image formed by certain optical systems for a given object. The optical system may be just a mirror, or a lens or a combination of several reflecting and refracting surfaces. In such problems, first of all, we identify the sequence in which the reflection and refraction are taking place.<\/p>

    All cases of reflections and refractions are governed by \u2018laws of reflection\u2019 and \u2018laws of refraction\u2019 respectively.<\/p>

    BASIC LAWS of Geometrical Optics:<\/strong><\/h4>
    1. Law of Rectilinear Propagation of Light <\/strong>states that \u201clight propagates in straight line in a homogeneous medium\u201d.<\/li>
    2. Law of Independence of Light Rays <\/strong>states that \u201cray do not disturb each other upon intersection\u201d.<\/li>
    3. Law of Reversibility of Light Rays <\/strong>states that \u201cwhen a ray of light is moved in opposite direction after going through a number of reflections and refractions, it retraces the path through which it was incident\u201d.<\/li><\/ol>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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