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The Simple Demonstration of the Photoelectric Effect

Eknath V. Maratha, St. Catharines, Ontario

In 1900, Max Planck worked out a relatively simple energy radiation equation for a black body that described the distribution of radiation accurately over the entire range of frequencies. His equation was based on a crucial assumption: radiant energy is not infinitely subdivisible. Like matter, it exists in “particles.” These particles Planck called quanta, or in the singular, “quantum.” He further suggested that the size of the quantum, also known as “photon,” for any particular form of electromagnetic radiation, was in direct proportion to its frequency. In the visible spectrum, a photon of violet light would therefore contain more energy than a photon of red light. The small constant that is the ratio of the energy of a photon (E) and the frequency(v) of the photon radiation is called Planck’s constant and it is symbolized as h = E/v). It is now recognized as one of the fundamental constants of the universe. Planck’s theory, known as Quantum Theory, was applied by Einstein in explaining the photoelectric effect. Read More...

Classroom Demonstration of Spectra

Jim Hunt, Physics Department, University of Guelph

The availability of large sheets of plastic replica gratings has greatly increased the ability to show spectra to classroom-sized groups and, in the process, put on a nice light-show. Read More...

Demonstrations Just for Fun

Roily Meisel, Ridgeway Crystal Beach High School

The three demos described here are, to the best of my knowledge, nowhere in the Ontario curriculum, although I stand to be corrected. Sometimes we need to do things because they are interesting and fun, and not solely because they are “on the course”. Read More...
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