Quantum Theory was the second of two theories which drastically changed the way we look at our physical world today, the first being Einstein’s Although both theoriesrevolutionized the world of physics, the QuantumTheory required a period of over three decades todevelop, while the Special Theory of Relativitywas created in a single year. The development ofthe Quantum Theory began in 1887 when aGerman physicist, Heinrich Hertz, was testingMaxwell’s Theory of Electromagnetic Waves.Hertz discovered that ultraviolet light dischargedcertain electrically charged metallic plates, aphenomenon that could not be explained byMaxwell’s Wave Theory. In order to explain thisphenomenon termed the photoelectric effect,because both light and electricity are involved, theQuantum Theory was developed. ThePhotoelectric Effect Maxwell’s work with theTheory of Electromagnetic Waves may seem tohave solved the problem concerning the nature oflight, but at least one major problem remained.There was one experiment conducted by Hertz,the photoelectric effect, which could not beexplained by considering light to be a wave. Hertzobserved that when certain metals are illuminatedby light or other electromagnetic radiation, theylose electrons. Suppose we set up an electriccircuit. In this circuit the negative terminal of abattery has been connected to a piece of sodiummetal. The positive terminal of the battery isconnected through a meter that measures electriccurrent, and to another piece of metal. Both ofthese metal plates are enclosed in a sealed glasstube in which there is a vacuum. When there is nolight illuminating the sodium plate, no current willflow, and therefore there is no reading on themeter. A reading on the meter will only occurwhen electrons are liberated from the metalcreating a flow of electric current. However, if thesodium plate is exposed to light, an electric currentwill flow and this will register on the meter. Byblockin...
