Question

A department store sells an ""astronomical telescope"" with an objective lens of 30 cm focal length and an eyepiece lens of focal length 5 mm. What is the magnifying power of this telescope?

Answer 1

Answer:

The magnifying power of this telescope is (-60).

Explanation:

Given that,

The focal length of the objective lens of an astronomical telescope, $f_o=30\ cm$

The focal length of the eyepiece lens of an astronomical telescope, $f_e=5\ mm=0.5\ cm$

To find,

The magnifying power of this telescope.

Solution,

The ratio of focal length of the objective lens to the focal length of the eyepiece lens is called magnifying of the lens. It is given by :

$m=\dfrac{-f_o}{f_e}$

$m=\dfrac{-30}{0.5}$

m = -60

So, the magnifying power of this telescope is 60. Therefore, this is the required solution.