The energy required to stop ejection of electrons from a Cu plate is `0.24 eV` .Calculate the work function Cu when a radiation of wavelength `lambda = 250` nm strikes the plate

Explanation

`KE = 0.24eV xx 1.6 xx 10^(-19) = 3.84 xx 10^(-20)J`
`E_(Total) = (6.63 xx 10^(-34) J s xx 3xx 10^(8) ms^(-1))/(250 xx 10^(-9)m)`
`= 7.956 xx 10^(-19) J`
Work function =` (E_("Total") - KE)`
`= (7.956 xx 10^(-19) - 0.384 xx 10^(-19))`
`= 7.572 xx 10^(-19)J "atom"^(-1)`
`= 7.275 xx 10^(-19) xx N_(A) J "mol"^(-1)`