Question

In a system with two thin lenses in contact, how do you find the focal length of one of the lenses given: the object distance, the image distance, and focal length the other lens?

Answer 1

using the given lengths calculate the NET focal length.(lens formula) when lenses are placed in contact, power adds up, ie 1/f1 + 1/f2 = 1/F(net). putting values simply yields the result..