Question

Work function of the metal is 4ev.to. to eject the photo electrons with zero velocity the wave length of the incident light should be

Answer 1

The work function for a metal is 4eV.To emit a photon-electron of zero velocity from the surface of the metal,the wavelength of incident light should be

(a)2700A∘(b)1700A∘(c)5900A∘(d)3100A∘

A)  

hV=work function +K.E

Given K.E=0

hV=4eV

4=12375λ

(where λ is in A∘)

∴λ=3100A∘

Hence (d) is the correct answer.