• Question: How powerful is your laser ? (by the way, my science teacher loved your joke)

    Asked by maddieduffy to Adam on 12 Nov 2013.
    • Photo: Adam Murphy

      Adam Murphy answered on 12 Nov 2013:


      Hey Maddie,

      I had to go look at my laser and take a look. At it’s brightest, my laser is about 200 milliwatts in power. Which is about a 500 times less that a light bulb. And that makes it sound not very good.

      But the thing to remember is that a light bulb has to light a whole room, and my laser just lights a tiny spot! The important thing with lasers isn’t just their power, but their intensity. (Intensity is how much power is in a certain area). My laser’s spot is, at most, 0.5 centimetres squared. So, one divided by the other says: My laser’s intensity is about 40 watts per square metre, which isn’t too shabby.

      The other thing is that the energy each packet of light (photon) contains depends on its colour. And blue light has the most of all the colours we can see.

      Those two things together mean my laser probably can’t set anything on fire, but it would blind you the second you looked into it!

      And tell your teacher they have great taste in jokes!

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