Using Einstein's equation, KE = hf - W₀. The kinetic energies will be KE₁ = 2eV - 1eV = 1eV, and KE₂ = 5eV - 1eV = 4eV. Since KE = ½mv², speed v ∝ √KE. The ratio of speeds v₁/v₂ = √KE₁/√KE₂ = √1/√4 = 1/2.