Here work function,ϕ0=0.5eV According to Einstein’s photoelectric equation Maximum kinetic = Incident - Work function energy of the emitted photon electrons energy ∴Kmax1=1eV−0.5eV=0.5eV......(i) and Kmax2=2.5eV−0.5eV=2eV.....(ii) Divide (i) by (ii), we get