I need help with these questions.

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.

What causes different colors to appear in the sky? the absorption of light by air molecules the reflection of light by bodies of water the greenhouse effect in earth's atmosphere the scattering and reflection of light by dust particles

What is the solubility-product constant of barium sulfate, baso4, if a saturated solution is 1.03 ´ 10-5 m?