What are bacteria? Are they good or bad?

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.

If two identical atoms are bonded,what kind of molecule is formed

How is the way a mixture is combined different from how a compound is combined?