Thanks to Einstein's equation E = mc² we now know that energy is equivalent to what?

How many moles is 14.5 cm^3 of platinum? the density of platinum is 21.45 g/cm^3.

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.

Which description best characterizes the motion of particles in a solid?