Question

A 5 cm tall object is placed perpendicular to the principal axis of a concave lens of focal- length 20 cm. The distance of the object from the len is 30 cm. Find the: (i) position (ii) nature (iii) size of the image formed.​

Answer 1

Answer:

h= 5

f= 20

u = -30

v = ?

h' = ?

1/u + 1/v = 1/f

1/v = 1/f - 1/u

= 1/20 - 1/-30

= 1/20 - 1/30

= 3 - 2/60

= 1/60

v = 60

image is at 60 cm from the lens, and it is virtual.

m = v/u

h'/h = v/u

h'/5 = 60/-30

h' = -10 cm

Size is diminished.