An Astronomical Telescope Has an Objective Lens with Focal Length

Multiple Choice

An astronomical telescope has an objective lens with focal length f_o and has an eyepiece with focal length f_e. A second telescope has objective and eyepiece lenses with half the focal length of the first telescope. Which telescope gives the greater magnification and by what factor?

A) The second telescope gives 4 times the magnification of the first.
B) The first telescope gives 4 times the magnification of the second.
C) The actual focal lengths must be known to answer this question.
D) Both telescopes give the same magnification.