Iron has a work function (φ) of 4.50 ev. what is the longest wavelength of light that will cause the ejection of electrons? (1 ev=1.6 × 10⁻¹⁹ j)

Growing crops in places where major pests don't live using beneficial insects to eat harmful insects using a rat trap instead of a rodenticide developing drought-resistant tomato plants using beneficial insects or natural oils to repel pests planting a different crop every year to fake out the pests keeping food covered to deter ants and rodents developing bean plants with a resistance to fungus picking caterpillars off tomato plants cultivation practice biological control cultural control genetic resistance natural chemicals