Electricity Flashcards
Define current
The charge that flows past a point in one second (rate of flow of charge)
Define 1 coulomb
The charge that flows in 1s when the current is 1A
Define potential difference
The work done per unit charge
What is ohms law?
The pd across a metallic conductor is directly proportional to the current running through it, provided the physical conditions do not change
What is an ohmic component?
A component that obeys ohms law
Define resistance
Voltage/ current
Define resistivity
(Resistance x cross-sectional area)/ length
Define superconductivity
When a material has 0 electrical resistance when cooled below the critical temperature
Define critical temperature
The temperature at or below which a material becomes a superconductor
Define internal resistance
The loss of potential difference per unit current in the cell when a current passes through the cell
Define electromotive force (EMF)
The electrical energy produced per unit charge passing through the source
What is a potential divider?
A combination of resistors in series connected across a voltage source to produce a required p.d
What is meant by an ideal ammeter and voltmeter?
Ammeter: resistance is 0
Voltmeter: resistance is infinite
What are some applications of superconductors?
- very strong electromagnets
- reduces energy loss in power cables
