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Homework Help: Questioning photoelectric effect theory

  1. Jan 14, 2005 #1
    I'm working on a lab where I used LEDs of different wavelenths to record photocurrent they create when striking a metal. Using this data, i was able to find an equation relating the wavelength of the incident light to the current that is produced.
    My problem is that when I repeated the experiment with different light sources (HeNe Laser, Hg lamp), the retarding potentials did not fit with the data from the LED's. The photoelectric effect says that the only thing that matters in the incident light is its frequency, because things like intensity are irrelevant. So I don't see why different light sources should create different currents. I don't know if what I said made any sense, but can anyone help me out here? Basically I'm asking if there are any other factors that would effect the current produced through the photoelectric effect other than frequency. I hope someone out there can help me out. thanks
  2. jcsd
  3. Jan 14, 2005 #2
    Right and wrong.. the retarded potential is related to its frequency only, but the current is affected by its intensity,

    different light sources has different frequence.. for example.. a red light has a lower frequence than a blue light.. surely you won't get a same result using different light source..

    different light source not only have different frequency (color), their intensity (strength) varies, too..
    Last edited: Jan 14, 2005
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