A small photocathode is illuminated by an isotropic monochromatic point source. Initially the source has optical power P, wavelength 500 nm and is at distance r from the photocathode. The saturation current is 80 μA. The source is then replaced by another source of power 2P and wavelength 250 nm, and the photocathode is placed at distance 2r. Assume the photocathode area, orientation and quantum efficiency remain unchanged, and both wavelengths are above threshold. What is the new saturation current?
Physics · Photoelectric effect and dual nature of matter · question based on photoelectric effect
A small photocathode is illuminated by an isotropic monochromatic point source. Initially the source has optical power P, wavelength 500 nm and is at distance r from the photocathode. The saturation current is 80 μA. The source is then replaced by another source of power 2P and wavelength 250 nm, and the photocathode is placed at distance 2r. Assume the photocathode area, orientation and quantum efficiency remain unchanged, and both wavelengths are above threshold. What is the new saturation current?
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