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:

we can try to form sharp image of distant objects on a screen formed by the combination of lens. So the distance between lens and screen is focal length of the combination.