Question

An object is placed to the left of a lens, and a real image is formed to the right of the lens. The image is inverted relative to the object and is one-half the size of the object. The distance between the object and the image is 66 cm. (a) How far from the lens is the object? (b) What is the focal length of the lens?

Answer 1

As given from the data that the image so formed is real and inverted and to the right of the lens, lens will be thin lens.

Now, the distance between object and image is 66cm. and the image is one-half the size of object, so,

Part A:

So, using the following notations:

as:

and  

Part B:

Using thin lens equation: