Calculate the valocity of a photoelectron if the work function of the target material is `1.24eV` and the wavelength of incident light is `4.36xx10^(-7)`m. What retarding potentia is necessary to stop the emission of the electrons?

Calculate the valocity of a photoelectron if the work function of the

1.	Calculate the valocity of a photoelectron if the work function of the target material is `1.24eV` and the wavelength of incident light is `4.36xx10^(-7)`m. What retarding potentia is necessary to stop the emission of the electrons?
Answer» We know that `(1)/(2)mv^(2)=hf-phi` or `(1)/(2)mv^(2)=(hf)/(lamda)-phi` Subsituting the values, we get `v=7.43xx10^(5)ms^(-1)`. Let `V_S` be the retarding potential required to stop the emissions of photoelectrons. Then, we have `eV_s=(1)/(2)mv^(2)` `impliesV_S=((1)/(2)mv^(2))/(e)=(2.511xx10^(-19))/(1.6xx10^(-19))=1.58V`

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