A photon with a momentum of 228 Times 1027 kg ms illuminates

A photon with a momentum of 2.28 Times 10^-27 kg m/s illuminates a metal sheet, which of the following metals will release electrons? Iron: 4.5 eV Cesium: 2.1 eV Aluminum: 4.08 eV Copper: 4.70 eV Sodium: 2.3 eV Platinum: 6.35 eV Zinc: 4.31 eV

Solution

momentum, p = 2.28 x 10^-27 kg m/s

energy = p c   = (2.28x 10^-27)(3 x 10^8)

E = 6.84 x 10^-19 J

E (in eV) =(6.84 x 10^-19)/(1.6 x 10^-19)

            = 4.275 eV

this is the energy of photon. hence sheets which have work fucntion less than 4.275eV

from them electron will be ejected.

Ans- Cesium, Aluminium, Sodium,