Question

(CBSE 2014)
(18) Explain the following terms related to Spherical lenses:-
a) Centres of curvature
b) principal axis
c)optical centre
d) Principal focus.
At what distance from a concave lens of local length
20 cm, should a 6 cm tall object be placed so that it forms an image at 15cm from the lens? Also determine the
size of the image formed.

(19) what is meant by power of a lens ? Name and define
its S.I. unit one student uses a lens of focal length +50
cm and another of - 50cm. state the nature and find the
power of each lens. which of the two lenses will always
give a virtual, erect and dimished image irrespective of
the position of the object ?
(CBSE 2014)​

Answer 1

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Please write this Question clearly...It is having so much spaces between it & I can't understand the Question...❣️