Light of wavelength 4000 Ao is incident on a metal plate whose work function is 2 eV. What is maximum kinetic energy of emitted photoelectron?

If the maximum kinetic energy of photoelectrons emitted from metal surface is Eo and W is the work function of metal thenEk=hv-Wwhere Iv is the energy of photon absorbed by the electron in metal.∴Ek=hcλ−Wwherev=cλPutting  the  numerical  values,  we  haveEk=6.6×10−34×3×1084000×10−10×1.6×10−19−2eVEk=3.1−2=1.1eV