This is because electromagnetic waves travel at different speeds through different media. This is called refraction and it causes the pencil to appear broken or bent. Electromagnetic waves are not compression waves. The speed of electromagnetic waves is fastest in a vacuum; the waves slow as the medium becomes denser.

The graph represents a weak acid. Acid HA only partially disassociates to form ions. Notice that hydrogen ions are donated to the water, creating hydronium ions and an acidic solution.

The correct answer is The electron will collide with the negative plate. The electron and the plate both have negative charges, meaning they will repel. Mass number is determined by the numbe rof protons and neutrons in the nucleus of the atom. Therefore, the statement each element would have a mass number of 12 would be false.