Question

is negative, it is a concave lens
Ir an object is kept at 26 cm from the lens, the
image will be virtual, erect and smaller than the
object.
(Note: The nature of the image is independent of the object
distance as it is a concave lens.)
(35) An object is placed in front of a convex
lens of focal length 20 cm. If the object distance
is changed from 60 cm to 40 cm, what can you
1 dioptre (D) 1 metre
INote: The dioptre, the SI
by DJ
(38) What is the sig
convex lens (ii) a con
Ans. The power of a
that of a concave lens i
(39) If there is an i
focal length of a lens
the power of the ler
Ans. The power of
length. Hence, if the
length of a lens, the
accordingly. Similar
focal length of a le
increase according!
say about the size of the image relative to that
of the object?
Ans. In this case, the focal length (ſ) of the lens
is 20 cm.:28 = 40 cm. When the object distance is
60 cm (which is greater than 2 f), the image will be
smaller than the object. When the object distance
becomes 40 cm (which is equal to 2 f), the image
will be of the same size as that of the object.
192
SCIENCE AND TECHNOLOGY (Part - 1) DIGEST : STD. X​

Answer 1

$\huge{\overline{\underline{\bf{what is que}}}}$