CHAPTER 8 Flashcards
ELECTRIC CURRENT
the rate of flow of charge, normally a flow of electrons in metals or a flow of ions in electrolytes
ELECTRIC CHARGE
a physical property, either positive or negative, measured in coulombs as a relative charge
ION
an atom that has either lost or gained electrons and so has a net charge
RELATIVE CHARGE
a simplified measurement of the electric charge of a particle or object, measured as multiples of the elementary charge
ELEMENTARY CHARGE
the electric charge equivalent to the charge on a proton, 1.60 x 10^-19
QUANTISED
the availability of some quantities, such as energy or charge, only in certain discrete values
FREE ELECTRONS
an electron in a metal that is not bound to an atom and is free to move- sometimes called a delocalised electron
CONVENTIONAL CURRENT
a model used to describe electric current in a circuit, conventional current travels from positive to negative, it is the direction in which positive charges would travel
ELECTROLYTE
a liquid containing ions that are free to move and so conduct electricity
IONIC SOLUTIONS
an ionic compound dissolved in a liquid to form an electrolyte
CATIONS
a positively charged ion which is attracted to the cathode
ANION
a negatively charged ion which is attracted to the the anode
CATHODE
a negatively charged electrode
ANODE
a positively charged electrode
RESISTANCE
a property of a component calculated by dividing the potential difference across it by the current in it
CONSERVATION OF CHARGE
a conservation law which states that electric charge can neither be created nor destroyed- the total charge in any interaction must be the same before and after the interaction
KIRCHOFF’S FIRST LAW
at any point in an electrical circuit, the sum of the currents into a point is equal to the sum of the currents out of that point, electrical charge is conserved
NUMBER DENSITY
the number of electrons per cubic metre of a material
SEMICONDUCTOR
a material with a lower number density than a typical conductor, e.g. silicon
MEAN DRIFT VELOCITY
the average velocity of electrons as they move through a wire
