Question

A convex lens is used in the experiment of conjugate focus method where image of the object is formed in the same place for two positions of the lens. The size of image in 1st position is 4cm and in the second position is 16cm . The length of the object is

Answer 1

Need homework help? Click here.

Need revision notes? Click here.

If m is the magnification in the first 

position then 1/m is the magnification

In the second position

Therefore size of object is equal to root under 4×6=8cm