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In this lesson, we will learn how to calculate the imaging properties of reflecting, refracting, and compound optical systems used in telescopes.
What is the angular magnification of a telescope that
has a 100 cm-focal length objective and a 2.50 cm-focal
A 7.5x binocular produces an angular
, acting like a telescope. (Mirrors are
used to make the image upright.) If the binoculars have
objective lenses with a 75.0-cm focal length, what is the
focal length of the eyepiece lenses?
A large reflecting telescope has an objective mirror
with a 10.0-m radius of curvature. What angular
magnification does it produce when a 3.00 m-focal length
eyepiece is used?
A planet at a distance of
m from Earth is observed by a telescope that has a focal length of the eyepiece of 1 cm and a focal length of the objective of 1 cm. The planet is seen to subtend an angle of
rad at the eyepiece. What is the size of the planet?
Two stars that are
apart are viewed by a
telescope and found to be separated by an angle of
radians . If the eyepiece of the telescope has a focal
length of 1.5 cm
and the objective has a focal length of 3
meters, how far away are the stars from the observer?
A telescope can be used to enlarge the diameter of a laser beam and limit diffraction
spreading. The laser beam is sent through the telescope in the direction opposite to the
normal one and can then be projected onto a satellite or the Moon. This is done with a
telescope, producing a 3.50 m diameter beam of 630 nm wavelength light.
What is the minimum angular spread of the beam produced?
Neglecting atmospheric effects, find the size of the spot this beam would make on the Moon.
Use a value of
m for the distance to the Moon.
In a reflecting telescope, the objective is a concave mirror of radius of curvature
4.0 m and the eyepiece is a convex
lens of focal length 6.0 cm. Find
the apparent size of a 5.0 m tree at
20 km that you would perceive
when looking through the telescope.
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