Question

The ejection of the photoelectron from the silver metal in the photoelectric effect exeriment can be stopped by applying the voltage of `0.35 V` when the radiation `256.7 nm` is used. Calculate the work function for silver metal.

Answer 1

`lambda_(256.7 nm = 256.7 xx10^(-9)m"","" K.E.=0.35 eV`
`E=(hc)/(lambda)=((6.626xx10^(-34)Js)(3xx10^(8) m s^(-1)))/((256.7xx10^(-19)m))`
`=(6.626xx3)/(256.7)xx10^(-17)J=(6.626xx3xx10^(-17))/(256.7xx1.602xx10^(-19))eV`
`=(662.6xx3)/(256.7xx1.602)eV=4.83 eV`
`E=E_(0)+K.E.`
`4.83 eV = E_(0)+0.35 eV`
`E_(0)=4.83-0.35=4.48eV`