The microscope available in your biology lab has a converging lens (the eyepiece) with a focal length of 2.50 cm mounted on one end of a tube of adjustable length. At the other end is another converging lens (the objective) that has a focal length of 1.00 cm. When you place the sample to be examined at a distance of 1.30 cm from the objective, at what length will you need to adjust the tube of the microscope in order to view the sample in focus with a completely relaxed eye?
Note that to view the sample with a completely relaxed eye, the eyepiece must form its image at infinity.