• Question: what is a photon?

    Asked by to Anna, Elaine, Fiona, Kevin, Darren on 25 Jun 2014. This question was also asked by .
    • Photo: Zhiming Darren Tan

      Zhiming Darren Tan answered on 25 Jun 2014:

      Simply put, it is a “particle” of light. Nowadays we think of light as both a particle and a wave – it is a “quantum” particle and has wave-like properties. So we call a particle of light a photon. When you switch on the light in your room, so many photons are given off that you can just treat it as a wave, as a beam of light. But in the laboratory, we have (laser) light sources that are very precise and light detectors that are so sensitive that they can detect even a single photon of light (ok, maybe a little exaggerated but not by much).

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