Electricity Key Words Flashcards
Electron
Negatively charged sub-atomic particle
Electron flow
The movement of electrons (usually around a circuit), from - to +
Insulator
A material with a small number density of conduction electrons and therefore a high resistance
Internal resistance
The resistance of a battery or cell, measured in ohms
I-V Characteristic
A graph to show how the electric current through a component varies with the potential difference across it.
Kirchhoff’s first law
The sum of the currents entering any junction is equal to the sum of the currents leaving the junction
Kirchhoff’s second law
The sum of the e.m.f.s is equal to the sum of the p.d.s in a closed loop
LDR
A component that changes its resistance with changes in light intensity
LED
A component that only allows electric current to pass in one direction and that emits light when p.d. is applied across it
Ohm’s law
The electric current through a conductor is proportional to the potential difference across it, provided that physical conditions, such as temperature, remain constant
Parallel circuit
A type of circuit where the components are connected in 2 or more branches and therefore provide more than 1 path for the electric current
Potential difference
The electrical energy transferred per unit charge when electrical energy is converted into some other form of energy
Potential divider
A type of circuit containing 2 components designed to divide up the p.d. in proportion to the resistances of the components
Resistance
A property of a component that regulates the flow of current through it
Resistivity
The ratio of the product of resistance and cross-sectional area of a component to its length
Series circuit
A type of circuit where the components are connected end to end and therefore provide only one path for the electrical current
Thermistor
A component that changes its resistance depending on its temperature
Volt
The unit of p.d. and e.m.f.
Components
Parts of electric circuits l, including bulbs, LDRs, thermistors etc.
Conductor
A material with a high number density of conduction electrons and therefore low resistance
Conventional current
A model used to describe the movement of charge in a circuit travelling from + to -
Coulomb
Unit of electrical charge (C)
Efficiency
The ratio of useful output energy to total input energy
Electric current
A flow of charge
An SI quantity, measure in amperes; a vector quantity
Electrolyte
A fluid that contains ions that are free to move and hence conduct electricity
E.M.F
The electrical energy transferred per unit charge when one form of energy is converted into electrical energy, measured in volts
