(c) Living things require oxygen for respiration. Fuels require oxygen for burning. Air contains much
more nitrogen than oxygen. Is it a good thing to have more oxygen than nitrogen in air? Explain
briefly.

Which theory was contradicted by experiments with the photoelectric effect? light spreads out after it passes through a small opening. as soon as light strikes metal, electrons will be ejected. visible light, regardless of color, will cause the ejection of electrons when striking metal. the kinetic energy of ejected electrons depends on the frequency of light that strikes the metal.