Authors: Preeti Chalsani, Ralph Greco
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Abstract: Light emitting diodes (LEDs) are increasingly being used as indicators in electronic devices and as efficient light sources such as traffic lights. Using super-bight LEDs, students investigate the conversion of electrical energy into light and vice versa. By measuring and comparing the energy lost by each electron with the frequency of the emitted light for several LED colors students estimate Plank's constant, a fundamental number of quantum mechanics.