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Explain effect of frequency of incident radiation in th experiment of photoelectric effect. |
Answer» Solution :Figure shows graph of variation of frequency of incident radiation at constant intensity in the experiment of photoelectric effect.  For different frequency of incident radiation stopping potential value obtained is different but saturation current is same. For frequency `V_(3)gtV_(2)gtV_(1)`,then stopping potential obtained also will be `V_(03)gtV_(02)gtV_(01)`. From this it can be said that when frequency of incident radiation is more then its energy of phtoelectron emitted will depend on enrgy (frequency) of incident radiation. When energy of photoelectron is more then more disaccelerating voltage (stopping potential) is required to stop them. For different METALS if graph of frequency of incident radiation and CORRESPONDING stopping potential is drawn then it will be a straight line as shown in figure.  Graph shows that: (i)For given photosensitive surface ,stopping potential varies linearly with frequency . (ii)For given minimum cut-off frequency `V_(0)` stopping potential will be zero. The above observatio suggest that: (i)Maximum kinetic energy of photoelectron varies linearly with frequency.But it does not depend on intensity. (ii)When frequency of incident radiation is less than cut-off frequency `V_(0)` the photoelectric emission will not take PLACE for any large value of intensity. |
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