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Define (1) threshold frequency (2) threshold wavelength (3) stopping potential. |
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Answer» (1) The threshold frequency for a given metal surface is the characteristic minimum frequency of the incident radiation below which no photoelectrons are emitted from that metal surface (whatever may be the intensity of incident light). (2) The threshold wavelength for a given metal surface is the characteristic maximum wavelength of the incident radiation above which no photoelectrons are emitted from that metal surface (whatever may be the intensity of incident light). (3) The stopping potential is the value of the retarding potential difference that is just sufficient to stop the most energetic photoelectrons emitted from reaching the collector so that the photoelectric current in a photocell reduces to zero. [Note : The threshold wavelength λ0 = c/v0, where c is the speed of light in free space and v is the threshold frequency for the metal.] |
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