what is the difference between the lithium and helium atoms?
a.
lithium is much smaller than helium.
b.
there is no difference between helium and lithium.
c.
lithium has more protons, neutrons and electrons.
d.
helium has more protons, neutrons, and electrons.

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.