A department store sells an "astronomical telescope" with an objective lens of 30-cm focal length and a diameter of 5 cm, and an eyepiece lens of focal length 5 mm and diameter 4 mm. What is the magnifying power of this telescope?
A) 6×
B) 150×
C) 60×
D) 12.5×

Question

Quizplus · Accepted Answer

The magnifying power of a telescope is given by the formula: Magnifying Power = Focal Length of Objective Lens / Focal Length of Eyepiece Lens. Here, the focal length of the objective lens is 30 cm (or 300 mm) and the focal length of the eyepiece lens is 5 mm. Therefore, the magnifying power is 300 mm / 5 mm = 60×.

A Department Store Sells an "Astronomical Telescope" with an Objective