Question

question 11
1 pts
a telescope has a focal length of 400mm. what focal length eyepiece is needed to achieve 100x magnification?
4mm
1mm
10mm
100mm
none

Explanation:

Step1: Recall magnification formula

The magnification formula for a telescope is $M=\frac{f_o}{f_e}$, where $M$ is the magnification, $f_o$ is the focal - length of the objective and $f_e$ is the focal - length of the eyepiece.

Step2: Rearrange the formula to solve for $f_e$

We can rewrite the formula as $f_e=\frac{f_o}{M}$.

Step3: Substitute given values

Given that $f_o = 400$ mm and $M = 100$. Then $f_e=\frac{400}{100}=4$ mm.

Answer:

4mm