The work function for a certain metal is 4.2 eV. Will this metal give photoelectric emission for incident radiation of wavelenght 330 nm?

Explanation

Work function =`phi_0 = 3.5 eV`
`lambda = 450 nm = 450 xx 10^(-9) m`
`lambda = 450 xx 10^(-8) m`
Energy of incident radiation = `E = (hc)/(lambda)`
`E = (6.62 xx 10^(-34) xx 3 xx 10^8)/(45 xx 10^(-8))`
`= (19.86)/45 xx 10^(-34 + 8 + 8)`
`= 0.44 xx 10^(-18)`
`E = 4.4 xx 10^(-19) J`
`E = 4.4 xx 10^(-19)J`
`E = (4.4 xx 10^(-19))/(1.6 xx 10^(-19)) eV`
`E = 2.75 eV`
As `E gt phi_0` , so radiation of wavelength 450 nm can eject a electron from the metal surface.