Question

Let us assume a system that consists of two lenses with focal length f1and f2
respectively. How do you find the focal length of the system experimentally, when
i) two lenses are touching each other
ii) they are separated by a distance ‘d’ with common principal axis.

Answer 1

Answer:

There are formulae for these:

1.(1/f)=(1/f1)+(1/f2)

2.(1/f)=(1/f1)+(1/f2)-(d/(f1*f2))

hope helps you