what is charge

Electric charge is a fundamental property of matter that governs how particles are affected by an electric or magnetic field. It is a conserved property, meaning that the net charge of an isolated system cannot change. Charge is carried by subatomic particles, with negative charge carried by electrons and positive charge carried by protons in the nuclei of atoms. If there are more electrons than protons in a piece of matter, it will have a negative charge, if there are fewer it will have a positive charge, and if there are equal numbers it will be neutral. Charge comes in two varieties: positive and negative, with positive charge being a property of protons and negative charge being a property of electrons. The charge on the proton is identical in size to that on the electron, but differs in sign. Charge is quantized, meaning it comes in integer multiples of individual small units called the elementary charge, e, which is the smallest charge that can exist freely. The SI unit of charge is the coulomb, symbol C, which is defined as the amount of charge on 6.241509 x 10^18 electrons. Like charges repel each other and unlike charges attract each other.