Electricity Flashcards
What direction do electrons flow around a circuit
Electrons flow away from the negative terminal of a cell towards the positive terminal. In the opposite direction to the conventional current.
State Ohms law
For a conductor at a constant temperature (constant resistance), the current through it is proportional to the potential difference across it.
V=IR
Define resistivity
Resistivity is a property that describes the extent to which a material opposes the flow of electric current through it
Thermistors are temperature sensors. As its temperature increases what happens to resistance?
As the thermistor gets hotter, its resistance decreases
How can the resistivity of a material be lowered?
The resistivity of a material can be lowered by lowering its temperature
How can the resistivity of a material be lowered?
The resistivity of a material can be lowered by lowering its temperature
What is a superconductor
A material with no resistance below a critical temperature
What is kirchhoff’s first law
At a junction in an electrical circuit, the sum of currents flowing into the junction is equal to the sum of currents flowing out of the junction.
What is Kirchhoff’s first law
At a junction in an electrical circuit, the sum of currents flowing into the junction is equal to the sum of currents flowing out of the junction.
What is Kirchhoff’s second law
The sum of the e.m.f’s in a closed circuit equals the sum of the potential differences.
Define EMF
The amount of chemical energy converted to electrical energy per coulomb of charge (C) when passing through a power supply
