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Q & A: Let there be (measured) light

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Most recent answer: 10/22/2007
how i can measure intensity of light
- maswood (age 21)
There are a number of ways of measuring the intensity of light. The first question is 'what kind of light are you measuring?'.  If ordinary daylight for photography, then a commercial selenium cell light meter is the right thing.  If you are talking about very, very faint light then you need something like a photomultiplier tube, along with its complicated electronics. If the light is infrared then you need a photo diode with appropriate sensitivity to low energy photons.
The common thread in all of these methods is that the light interacts with some material and ejects electrons.  The electrons then form a current that can be measured.
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(published on 10/22/2007)

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