y8 electricity + magnetism Flashcards
(24 cards)
conductor…
will allow energy to pass through it
insulator…
will not allow energy to pass through it
all metals ______ electricity
conduct
most non-metals __________ electricity
do not conduct electricity
an exception to this is graphite (carbon)
is pure or salt water a better conductor
salt > pure
current is…
the amount of charge flowing past a point every second
current is measured by _______ with the unit ______
an ammeter
ampere (amps)
the charged particles flowing through circuits are…
electrons
current in = __________
current out; charge must be conserved
energy per charge also called…
potential (unit is volts)
the current will be lower if there are more bulbs in the circuit because…
the extra bulbs cause more resistance in the circuit due to their thin wire filament
resistance is measured in…
ohms (omega symbol)
are all metals magnetic?
no, only iron, nickel and cobalt are. this explains convection due to magnetism as there is iron and nickel at the earth’s core
the same poles will…
repel
opposite poles will…
attract
you ______ stop a magnetic field
cannot
animals that have magnetoreceptors (use the earth’s magnetic field for navigation/orientation)
birds, sea turtles, bees, mole rats, sharks
what is an electromagnet
any wire with a current passing through it (it produces a magnetic field, therefore an electromagnet is created)
how can you increase the strength of an electromagnet
- increase the current (voltage)
- increase the turns on the coil
- add a soft iron core
uses of electromagnets
relays in x-ray machines
floodlights
motors in microwaves
maglev trains
rollercoaster brakes
doors (fire + security)
there is more resistance in a wire if..
it is longer/thinner
formula for resistance
resistance (ohms) = potential difference (V)/current (A)
energy per unit charge
potential
motor is a..
coil of wire between two magnets
