Q23 of 25 Page 10

To construct a ray diagram we use two rays of light which are so chosen that it is easy to determine their directions after reflection from the mirror. Choose these two rays and state the path of these rays after reflection from a concave mirror. Use these two rays to find the nature and position of the image of an object placed at a distance of 15 cm from a concave mirror of focal length 10 cm. ( CBSE 2015)

Ray1 When an incident ray is parallel to the principal axis of the mirror, its reflected ray must pass through the principal focus of the concave mirror or it appears to pass through the focus of convex mirror.

Ray2 When the principal ray passes through or appears to pass through the centre of curvature the light after reflection from spherical mirror emerges parallel to the principal axis.



The image formed is real, inverted and magnified. It is formed beyond the centre of curvature.


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A student wants to project the image of a candle flame on a screen 60 cm in front of a mirror by keeping the flame at a distance of 15 cm from its pole.(i) Write the type of mirror he should use.(ii) Find the linear magnification of the image produced.(iii) What is the distance between the object and its image?(iv)Draw a ray diagram to show the image formation in this case.( CBSE 2014)

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An object is placed on a metre scale at 8 cm mark was focused on a white screen placed at 92 cm mark, using a converging lens placed on the scale at 50 cm mark.(i)Find the focal length of the converging lens.(ii)Find the position of the image formed if the object is shifted towards the lens at a position of 29.0 cm.(iii)State the nature of the image formed if the object is further shifted towards the lens.
( CBSE 2013)