Question

The eyepiece of a compound telescope has a focal length of 12 cm and the objective lens has a focal length of 16 m. What is the overall magnification of the telescope?

Answer 1

Answer:

The magnification is 133X

Explanation:

For a refractor telescope using convex lenses, the overall magnification os calculated as by dividing the focal length of the objective by that  of the eyepiece.

$M = \frac{f(obj)}{f(eye)}$

So:

$M = \frac{16 m}{12 cm}$

Care must be taken with the units, in this case they are in meters and centimeters, they should be converted into the same unit before calculating:

$M = \frac{16 m}{0.12 m} = 133$