Here is a quesiton I am having trouble with :uhh: , thanks for your help. Electrons are ejected from a photoelectric surface with a maximum speed of 4.20 * 10^5 m/s. If the work function of this surface is 2.55 eV, what is the wavelength of the incident light? This is how i tried to solve this question: Ek=(1/2)mv^2 Ek=(1/2)(9.11*10^-31 kg)(4.20*10^5 m/s)^2 Ek=8.04*10^-20 J E=hc/λ λ=[(6.63*10^-34 Js)(3.00*10^8 m/s)]/(8.04*10^-20 J) λ=(2.48*10^-6 m) :yuck: The actual answer is (4.07*10^-7 m). Can you please tell me the correct way to do this question. Thanks.