In a refracting telescope, the angular magnification is M = fo/fe. If fo = 200 cm and fe = 25 cm, what is the magnification?

In a refracting telescope, the angular magnification is M = fo/fe. If fo = 200 cm and fe = 25 cm, what is the magnification?

• A. 2
• B. 8
• C. 10
• D. 20

Answer: (B)

In a refracting telescope, angular magnification comes from the ratio of the objective’s focal length to the eyepiece’s focal length. The magnification M equals fo divided by fe. With fo = 200 cm and fe = 25 cm, M = 200/25 = 8. So the telescope magnifies the angular size by a factor of 8.

In a refracting telescope, angular magnification comes from the ratio of the objective’s focal length to the eyepiece’s focal length. The magnification M equals fo divided by fe. With fo = 200 cm and fe = 25 cm, M = 200/25 = 8. So the telescope magnifies the angular size by a factor of 8.