Re: ray tracing assumptions

[Bob Sciamanda <trebor@VELOCITY.NET>]

Consider a virtual object to the right of a converging thin lens (light travel is left to right, and the optical axis is horizontal).  Three rays originally headed toward a given object point can easily be traced:

1) A horizontal ray originally headed at the object point refracts through the right focal point.

2) A ray passing through the left focal point and originally headed at the object point refracts into a horizontal ray.

3} A ray passing through the lens center and originally headed at the object point passes undeviated through the lens.

 

Things are only a little more complicated for a diverging lens.

 

Bob Sciamanda (W3NLV)
Physics, Edinboro Univ of PA (em)
trebor@velocity.net
http://www.velocity.net/~trebor

----- Original Message -----

From: James Mackey

To: PHYS-L@lists.nau.edu

Sent: Thursday, April 18, 2002 1:30 PM

Subject: Re: ray tracing assumptions

I have been following this discussion of ray tracing with interest.  I only use ray diagrams roughly to scale for students to approximately locate images as a check on calculations, and as a means to understand the general pattern of images for concave & convex lenses and mirrors.  I do not use them with multiple lens systems as are being discussed since I can see no easy way to produce the needed rays for the 2nd optical element to make quick and simple ray diagrams possible.  All of the calculations and discussions so far confirms that I do not want to do multiple lens/mirror ray diagrams.  For those systems calculations will suffice. If anyone knows an easy way to do this that students can do fairly quickly, I would like to see it.
James Mackey. . .