PH 102 Lecture Notes - Lecture 1: Gallium Arsenide
Document Summary
All materials can have a charge, which we refer to as either positive or negative . The origin of this charge is the makeup of an atom, which consists of a positively charged nucleus surrounded by negatively charged electrons. The nucleus consists of protons, which have positive charge, and neutrons, which have no charge. The charge of a proton is the same in magnitude but opposite in sign to that of an electron. In a neutral atom there are an equal number of electrons and protons and the net charge is zero. A material will have a net charge if it has a deficit or surplus of electrons. This will occur because the two materials have a different affinity for electrons. Like charges repel (e. g. , positive-positive or negative-negative), while unlike charges attract (positive-negative). Materials can be electrically classified by how well charges move through the materials. Examples of conductors are copper, silver, gold, and aluminum.
