1. Chang, R. and Goldsby, K. A.Chemistry,11th ed.McGraw-Hill:New York, 2013; Chapter 7.2, pp281–283.
2. Supplier: PASCO, Model SE-6609.http://www.pasco.com/(accessed Jan 2015) .
3. The Photoelectric Effect Using LEDs as Light Sources
4. Educational Innovations, Inc., Item #SS-910. http://www.teachersource.com/(accessed Jan 2015) .