What is wave-particle duality?

1 Answer
Jun 22, 2014

Wave-particle duality means that light behaves as a wave in some experiments. In other experiments, light behaves as a particle.

In 1801, Thomas Young shone light between two parallel slits. The light waves interfered with each other and formed a pattern of light and dark bands.

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If the light had consisted of small particles, they would have passed straight through the slits and formed two parallel lines.

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In 1905, Albert Einstein showed that a beam of light could eject electrons from a metal. He found that photons with a frequency over a certain level would have sufficient energy to eject an electron. The light was behaving as a stream of particles, like machine gun bullets.

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Hope this helps.