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Answer: The Photoelectric Effect</h2>
Light can be considered as a wave or as particles, in this context Einstein proposed that light behaves like a stream of particles called <u>photons</u> with an energy, in order to correctly explain the photoelectric effect.
This fenomenom consists in the emission of electrons (electric current) that occurs when light falls on a metal surface <u>under certain conditions.
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So, if we consider light as a stream of photons and each of them has energy, this energy is able to pull an electron out of the crystalline lattice of the metal and communicate, in addition, a <u>kinetic energy</u>.
This means the photoelectric effect can only be explained based on the corpuscular model of light, that is, light is quantized.
