Photoelectric

Photoelectric - Note-A-Rific Photoelectric Effect Hertz...

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Note-A-Rific: Photoelectric Effect Hertz Experiment In 1887 (about a decade before Planck did all his stuff to explain blackbody radiation) Hertz was trying to figure out a way to test Maxwell&s theories on electromagnetism. He set up an apparatus as shown here± While trying to make EM waves, he noticed that when certain metals are hit by ultraviolet (UV) radiation, the leaves of the electroscope spread apart. He theorized that when UV radiation hit the zinc plate it must liberate (set free) electrons. This became known as the ² Photoelectric Effect ³ photo ! light electric ! electricity Hertz didn&t develop this discovery much further. This didn&t disagree with the wave theory of light, since the electric field of an EM wave could be exerting a force on the electrons, forcing them out. Hertz Experiment Einstein Investigates Stopping Voltage Work Function Photoelectric Effect
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Einstein Investigates Photoelectric Effect At the beginning of the 1900&s Albert Einstein linked Hertz& research on the photoelectric effect to the work of Planck. Remember, Planck said that an object emits energy according to the formula E = nh ƒ . Einstein said that when an object emits light, the object must decrease its energy by that same amount± E= nh ƒ . So light must be released in ²packets³ of energy± Wait a second± he saying light is emitted as tiny particles , not waves ± He called these packets of light ² photons ³ To test his theory, Einstein examined the photoelectric effect. A device similar to this one was set up: Einstein ran several different tests with this apparatus. 1. What happens when the voltage source is turned off and the device is in the dark (no UV radiation falls on the plate)?
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Nothing happens. There are no readings on the ammeter, which is exactly what we would expect. As shown above, this is a broken circuit that (at the moment) has no voltage source. 2.
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Photoelectric - Note-A-Rific Photoelectric Effect Hertz...

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