ELECTRICITY Flashcards
thermistor
as temperature increases, resistance decreases. NTC (negative temperature coefficient).
Superconductor
Resistance = 0, at low temperatures, no power loss P= RI^2 if R=0.
emf
Work done per unit charge provided by battery
Why is there internal resistance
When the switch is closed, current flows through battery, producing lost volts.
Why’s it important for battery to have low internal resistance.
More energy supplied to battery. Battery will charge quicker.
what does an emf of 5.3V mean
Energy transferred from chemical energy to electrical energy is 5.30J of energy per coulomb of charge
Why is the voltmeter not the same as the battery
current in circuit changes as voltmeter position changes, because resistance in circuit changes
battery long side charge?
positive
Which way do electrons travel
positive to negative
pd definition
measure of how much energy is transferred by each Coulomb of charge.
current
rate of flow of charge
resistance
measure of how much a component resists the flow of current
power
rate of energy transferred
(Filament lamp) effect on resistance if current increases, refer to electron flow
resistance increases, more frequent collisions, energy transfer increases latice vibration
Energy equation that links Charge and Potential Difference
E = QV
