A simple camera telephoto lens consists of two lenses. The objective lens has a focal length of f1 = + 39 cm. Precisely 36 cm behind this lens is a concave lens with a focal length of f2= -10 cm. The object to be photograph is 4 m in front of the objective lens.
a) How far behind the concave lens should the film be placed?
b) what is the linear magnification of this lens combination?