Question

A convex lens forms a real image 16 mm long on
a screen. If the lens is shifted to a new position
without disturbing the object or the screen then
again a real image of length 81 mm is formed. The
length of the object must be​

Answer 1

Answer:

If the image sizes be I

1

and I

2

,

By Displacement Method, object size (OS) is given by :

OS=

I

1

I

2

Thus, OS =

64

⟹ OS=8

Explanation:

hope this is the answer

Answer 2

Answer:

let the image sizes be i1 and i2

By displacement method, object size (OS) is given by:

OS=√i1i2

thus, OS=√16×81=√1296=36