Modern Physics > Quantum Effects > Photoelectric Effect

DCS# 7A10.30

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PHOTOELECTRIC EFFECT

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APPARATUS
 

pasco photodiode circuit box	214B
mercury lamp	214B
filter set	214B
neutral density filter	214B
digital multimeter	214-02-B6
laptop	206

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DESCRIPTION Plot stopping voltage vs frequency for the four visible lines of mercury + one uv line.  Planck's constant can be obtained from the slope.  Use the neutral density filter to show that intensity doesn't affect the stopping potential.

NOTES
The frequencies of the visible lines in the mercury spectrum are:

yellow	5.187 x 1014 Hz
green	5.490 x 1014 Hz
blue	6.879 x 1014 Hz
violet	7.409 x 1014 Hz
ultraviolet	8.202 x 1014 Hz

The uv appears blue on the fluorescent white mask.

Press the zero button between readings.

REFERENCES Pasco h/e apparatus instruction manual.