Electricity Flashcards
(17 cards)
what is Kirchhoff’s first law?
conservation of charge
current going into a junction is equal to the current coming out of a junction
what is Ohms law?
V=IR, resistance is directly proportional to potential difference/inversely proportional to current
what is Kirchhoff’s second law?
conservation of energy
pd across a circuit is equal to the emf
what is current?
the flow of charge
how can gases become conductive?
when they become ionised
what are the characteristics of ohmic materials?
direct proportionality between pd and current
constant resistance when temp stable
steeper gradient = higher resistance
what is the definition of watt?
joule per second
what direction does conventional current flow?
positive to negative
what is the base SI unit for W?
kgm3s-2
what component has a straight line in an IV graph?
resistor
which component has a curved line in an IV graph?
filament lamp
what is intensity?
power per unit cross sectional area
what is the base SI unit for voltage?
kgm2s-3A-1
what is the base SI unit for resistance?
kgm2sA-2
how do you work out the internals resistance of a battery from a V-I graph?
minus gradient
how do you work out emf from a V-I graph?
y-intercept
