In this exercise students will examine three optical instruments, a simple magnifier,
a simple, refracting telescope, and a compound microscope.
Telescopes and Microscopes
After studying the reference material, go to blackboard
and complete Extra Credit 10.
You must answer the following questions.
The magnifying power of a small Keplerian telescope is 25
and the separation between its objective and eye piece is 52 cm in normal
The focal lengths of its objective and eye piece are respectively
--- and ---.
The focal lengths of the eye piece and objective
of a telescope are respectively 100 cm and 2 cm.
The moon subtends an angle of 0.5º at the eye.
If it is looked through the telescope, the angle subtended by the moon’s
image will be ---.
The length of a
Galilean telescope is given in terms of the focal lengths
of objective and eyepiece by ---.
When the object distance from a converging lens
is 5.0 cm, a real image is formed 20 cm from the lens.
What angular magnification is produced by this lens when it is used as a
In a compound microscope, the focal lengths of
the objective and eyepiece are +0.50 cm and +2.0 cm respectively.
The instrument is focused on an object 0.52 cm from the objective lens.
Compute the magnifying power of the microscope.