Question

A pirate sights a distant ship with a spyglass that gives an angular magnification of 26. Part A If the focal length of the eyepiece is 11 mm , what is the focal length of the objective? Express your answer using two significant figures. V ΑΣφ fobj cm Request Answer Submit Provide Feedback

Answer 1

given:

Here we need to determine the focal length of the objective lens. The magnification of the telescope is given to be $M_{total} = 26$ and the focal lengths of eyepiece lens is $f_{eye} = 11 mm$ and objective lens is $f_{obj}$.

We know that,

$M_{total} = \frac{f_{obj}}{f_{eye}}$

$f_{obj} = M_{total} \times {f_{eye}}$

$f_{obj} = 26 \times {11mm}$

$f_{obj} = 286mm$

$f_{obj} = 286mm \times \frac{1cm}{10 mm}$

$f_{obj} = 28.6 cm$