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Verification of inverse square law using photocell is straight line

  1. Apr 27, 2010 #1
    why the graph for the verification of inverse square law using photocell is straight line instead of a curve ?
    since intensity is inversely proportional to the distance then graph must be a curve, but why it is straight line ?
  2. jcsd
  3. Apr 27, 2010 #2
    Re: photocell

    This is because you are confusing the intensity of the source with the intensity of a reciever. A photocell works by allowing light into it. The light then gives energy to the electrons in the material. It does this to free the electrons from there bound state, so they can become "conduction electrons" and pass on a current. By "knocking off" the electrons, it reduces the resistance and allows a current to pass. The relationship between the current flowing through the LDR (photocell) is dependant on the reduction in resistance which is independant of the intensity coming in, as it is a discrete process of either giving energy to conduction electrons, or simply not.
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