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Light of frequency 7.21xx10^(14)Hz is incident on a metal surface. Electrons with a maximum speed of 6.0 xx 10^(5) m/s are ejected from the surface. What is the threshold frequency for photoemission of electrons? |
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Answer» Solution :`upsilon=7.21xx10^(14)HZ, v=6xx10^(5)ms^(-1)` `(1)/(2)mv_("max")^(2)=h(upsilon-upsilon_(0))=hupsilon-h upsilon_(0)` `h upsilon_(0)=h upsilon-(1)/(2)mv_("max")^(2)` `upsilon_(0)=upsilon-(1)/(2)(mv_("max")^(2))/(h)=7.21xx10^(14)-(1)/(2)XX(9.1xx10^(-31)xx(6xx10^(5))^(2))/(6.6xx10^(-34))=4.73xx10^(14)Hz` |
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