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What will be the path of ray passing through the first focal length of a biconcave thin lens kept in air?

I know that a ray passing through focus or appearing to pass through focus of a thin lens becomes parallel to the principal axis. But in this case I cannot see how? enter image description here

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The ray passing from the focus, after the lens overlaps with the one that starts from the tip of the virtual image, see the image. (Basically that ray is not a "special" one).

enter image description here

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  • $\begingroup$ But shouldn't a ray passing through the focus be parallel to the principal axis of the lens? $\endgroup$
    – Utkarsh Barsaiyan
    Feb 19, 2016 at 11:30
  • $\begingroup$ on a positive lens only. $\endgroup$
    – scrx2
    Feb 19, 2016 at 11:35
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    $\begingroup$ try this software to play with optics $\endgroup$
    – scrx2
    Feb 19, 2016 at 11:37
  • $\begingroup$ @Utkarsh Barsaiyan do you find the answer acceptable? if yes, consider accepting it $\endgroup$
    – scrx2
    Mar 17, 2016 at 21:02

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