Final answer:
The magnification of a telescope with an objective lens focal length of 120 cm and an eyepiece focal length of 6.0 cm is 20X.
Step-by-step explanation:
The magnification of a telescope is determined by the ratio of the focal length of the objective lens to the focal length of the eyepiece. In this case, the objective lens has a focal length of 120 cm and the eyepiece has a focal length of 6.0 cm.
To calculate the magnification, divide the focal length of the objective lens by the focal length of the eyepiece:
Magnification = Objective lens focal length / Eyepiece focal length = 120 cm / 6.0 cm = 20X
Therefore, the magnification of the telescope is 20X.