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Light of wavelength 2000 Å can just ejec...

Light of wavelength 2000 Å can just eject electrons from a metal surface. Calculate the work function of the metal.

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Given, `lambda = 2000 ` Å ` = 2 xx 10^(7) ` m, w = ?
We know that, `w = hv_(0) =(hc)/lambda`
`w = (6.625xx10^(-34)xx3 xx 10^(8))/(2xx10^(-7))=9.937xx 10^(-19) " J"= (9.937xx10^(-19))/(1.6xx10^(-19))=6.21` eV.
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