What must be true about two objects for conduction to take place? The objects must be different temperatures and they must be in contact. The objects must be the same temperature and they must be in contact. The objects must be different temperatures and they must be insulators. The objects must be the same temperature and they must be insulators

Which statement about sound is not true? a. air particles travel with sound waves. b. sound waves cannot travel through a vacuum. c. sound waves exist even if no one hears them. d. air particles vibrate along the path of a sound wave.

The characteristic of two different types of reactions are shown below. reaction a: electrons are gained by the atoms of an element. reaction b: protons are lost by the atom of and element. which statement is true about the atoms of the elements that participate in the two reactions? a: their identity changes in both reaction a and b. b: their identity changes in reaction a but not b. c: their identity changes in reaction b but not a. d: their identity remains the same.

Many ionic compounds and a few highly polar covalent compounds are because they completely ionize in water to create a solution filled with charged ions that can conduct an electric current.