Telescope in Milikan Experiment

[shehri]

Homework Statement

Homework Equations

My book mentions a telescope in order to measure velocities of electron.But does not explain why to use it?Plz. tell me why to use a Telescope?Thanks.

The Attempt at a Solution

 

[berkeman]

Could they mean microscope? AFAIK, Milikan's oil drop experiment was conducted in a small container, and small motions of the oil drops were being observed...

The drawing at the wikipedia.org entry for this experiment definitely calls it a "microscope":

http://en.wikipedia.org/wiki/Oil-drop_experiment