electricity Flashcards
voltage
the energy transfer per unit of charge in a circuit
units of voltage
Volts
current
the rate of flow of charge
symbol for current
I
units of current
amperes
what do you use to measure current
ammeter
what do you use to measure voltage
voltmeter
how do connect a voltmeter
in parrallel
how do you connect a ammeter
in series
Diodes
allows electricity to flow in only one direction
LED stands for…
Light emitting diode
conducters
components that allow electrons to flow through them
what are good conductors and why?
metals, delocalized electrons(free to move)
resistance
oppose the flow of electric current
rheostat
a variable resistor
how can you make a rheostat
changing length of resitor
how do light bulbs work
high resistance wire, current passes through and so wire heats up ad gets so hot it lights up
what type of energy conversion happens in light bulbs
electrical energy converted to light energy
cell
a source of electrical energy
battery
2 or more cells connected together
what type of wire do light bulbs have
tungsten(W) wire
what is the chemical name for tungsten
wolfram
conventional current direction
negative to positive
unit of measurement for resistance
ohms
what affects resistors
material, length, thickness, temperature
what is the exception for non-metals(they aren’t conductors)
graphite
how does the thickness of a wire effect the resistance
the thicker the wire the less resistance
how does the length of a wire effect the resistance
the longer the wire is the more resistance it has
what type of relationship does the length of the wire have to the current
inversely proportional
how does the temperature effect the resistance
the hotter the resistor the more resistance
what happens to the voltage in a parallel circuit
it stays the same throughout the circuit
what happens to the current in parallel circuit
it splits up into each branch(the total resistance of the circuit = current of each branch added)
what happens to the light bulbs brightness in a parallel circuit(if there is more than one)
they all have the same brightness
what happens to the current in a series circuit
the current stays the same throughout
if batteries are connected in series what is the total voltage
sum of voltage of each battery
what is the symbol for resistance
R
higher resistance means … current
lower
lower resistance means … current
higher
ohm’s law
V= I x R
what direction does the electronic current flow
positive to negative
