Optical Instruments


In this exercise students will examine three optical instruments, a simple magnifier, a simple, refracting telescope, and a compound microscope.

Reference material:  Telescopes and Microscopes

After studying the reference material, go to blackboard and complete Extra Credit 10.

You must answer the following questions.

Question 1:

The magnifying power of a small Keplerian telescope is 25 and the separation between its objective and eye piece is 52 cm in normal setting.
The focal lengths of its objective and eye piece are respectively --- and ---.

Question 2:

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 ---.

Question 3:

The length of a Galilean telescope is given in terms of the focal lengths of objective and eyepiece by ---.

Question 4:

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 magnifying glass?

Question 5:

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.