Question

27.Draw ray diagrams to describe the nature. position and relative size of the image formed
by a convex lens for the objeci
(b) When the object s placed at F. and
(ii) When the object is placed between F. and optical centre of the lens. (CBSE 2011.
28. Draw ray diagrams to describe the nature. position and relative size of the image formed
by a concave ens for the object
When the object is placed at nfinity and
(ii) When the object is placed to between
infinity and optical centre of the lens. (CBSE
2011. 2012)
29. A ray of light, ncident obliquely on a face of a rectangular glass slab placed in air.
emerges from the opposite face parallel to the incident ray. Draw labelled diagram to
show it. Slate two lactors on which the lateral displacement of the emergent ray
depends. (CBSE Foreign) 2008. 2013)
30. An object is placed at the following distances from a convex lens of focal length 15 cm.
(0) 35 cm
(1) 0 0
kiun) 20 cm
(iv10 cm
Which position of the object will produce an image of same size as that of the object ?
ICBSE 2011)
31. A lens X has focal length 20 cm and lens Y has focal length 40 cm. Which lens would
you select to obtain a more convergent beam of light ? (CBSE 2011)​

Answer 1

The case when object is between F¹

and the optical centre O of the lens shows the use of convex lens as a magnifying glass . This is because here the image formed is erect and magnified .