To construct ray diagrams, two rays of light are generally so chosen that it is easy to determine their directions after reflection from a mirror. Choose two such rays and state the path/direction of these ray other reflection from a concave mirror. Use these two rays to find the postion and nature of the image of an object placed at a distance of 8 cm from concave mirror of focal length 12 cm.

To construct ray diagrams, two rays of light are generally so chosen t

1.	To construct ray diagrams, two rays of light are generally so chosen that it is easy to determine their directions after reflection from a mirror. Choose two such rays and state the path/direction of these ray other reflection from a concave mirror. Use these two rays to find the postion and nature of the image of an object placed at a distance of 8 cm from concave mirror of focal length 12 cm.
Answer» Solution : RAYS which are chosen to CONSTRUCT ray diagram for reflection are: (i) A ray parallel to the principal axis and (ii) A ray passing through the CENTRE of curvature of a concave mirro or appear to pass through the centre of curvature of convex mirror. Path of these rays after reflection: (i) After reflection, it will pass through the principal focus of a concave mirror or appear to diverge in case of a convex mirror. (ii) After reflection, it is reflected back ALONG the same path. `f=-12cm,u=-8cm` we know `1/f=1/v+1/u` `1/v=1/f-1/u=1/(-12)-1/((-8))` `=1/8-1/12` `=(3-2)/24` `=1/24=24cm` v=+ve so image is virtual and is formed at a DISTANCE of 24 cm behind the mirror.