Question

the work function of cesium is 2eV.explain statement

Answer 1

Work function of a material is the minimum/threshold energy needed to remove an electron from a solid to a point in the vacuum immediately outside the solid surface. Therefore, the above statement means that a minimum of 2eV or 2*1.6*10-19J of energy must be incident on Cs for photoelectrons to come out of its surface. For energies less than 2eV, no photoelectric emission occurs.