Answer:
The correct wavelength of the light beams should be 350 nm, 500 nm, 450 nm, and 250 nm respectively. The term "life step" should be "light step." Additionally, "2.50el" should be "2.50 eV" to represent electron volts. The word "life" should be "light" in the question. The phrase "Calculate the corresponding generated electron velocity" should be "Calculate the velocity of the generated electrons."