To examine a particular blood sample in biology lab, a student uses a compound microscope set to have a magnification of -4520. The objective and eyepiece are both attached to a tube which is 18.5 cm in length and the eyepiece has a focal length of 2.51 cm. The near point of the person using the microscope is 24.5 and you can assume she can view the image produced with a fully relaxed eye.
What is the focal length of the objective?
What is the distance between the blood sample and the objective lens? do?