Static And Current Electricity Flashcards
Static Electricity
A build up of le trip charge that can occur on good insulators e.g. polythene and Perspex rods.
Polythene rod
Gains electrons if a woollen cloth is rubbed on it ( becomes negatively charged).
Perspex Rod
Loses electrons if it’s rubbed by a woollen cloth ( becomes positively charged).
What is an electric current?
An electric current is caused by the flow of electrons through a good conductor such as metal.
Closed circuits
A closed circuit is needed for the current to flow.
Batteries
Energy provided by a battery or power pack is needed to move the current around the circuit.
Potential difference
The difference in electrical pressure between the positive and negative ends.
Resistance
The opposition to the flow of electrons. The unit is the Ohm and it is measured using an Ohmmeter.
Ohm’s Law
Oh’ms law states that voltage is directly proportional to current .
Direct current
Direct current goes in one direction only.
Alternating Current
Changes very quickly many times a second.