Date: Tue Mar 31 12:34:04 2009 Back to Contents ------------------------------------------------------------------------

Author: Andy Dougherty

Subject: Re: LED photoelectric effect apparatus

Post:

On Mon, 30 Mar 2009, John Welch wrote:

> Hey all -
> we're making several homemade PE experiments using LED's, based on the
> article by Wayne Garver in the May 2006 Physics Teacher.

I looked at doing this too, but I made the "mistake" of trying to measure
the actual wavelength of the LEDs I had at hand, rather than relying on
the manufacturer's value. The LEDs had an extremely broad distribution of
wavelengths, easily verified by looking at one through a student
spectrometer. I've placed a graph at

http://www.lafayette.edu/~doughera/other/lab/LED-Green.png

This doesn't answer the question about the phototubes, of course, but does
make one wonder just what is actually being measured.

--
Andy Dougherty doughera@lafayette.edu
Dept. of Physics
Lafayette College, Easton PA 18042

From tap-l-owner@lists.ncsu.edu Tue Mar 31 12:34:04 2009