Magnets/electricity Flashcards
what’s a fundamental force
electromagnetism
coulombs law
1/4 x pi x E(o) // q1 x q2 /r2
E(o)
8.85 x 10(-12)
what’s potential difference
difference between highs and lows, its voltage, units volts
where does electric current flow?
from high potential to low
why does current flow?
electric potential
what’s current?
flow of charged particles, from high to low, positive to negative, units amps
current equation
current= charge/time
D.C
straight line, one direction, low power, small devices, most devices use this
charge units
coloumbs
A.C
wiggly line, both directions, large devices, can start current in unconnected circuits, long distance
what’s a conductor
impedes current flow
what’s a superconductor
doesn’t impede current flow
resistance/conductor equation
resistance = voltage/current
if you double the conductor you …
double resistance
resistivity equation
resistance= resistance of material x length/area
resistance units
ohms
metal/wood resistance
metal is low, wood is high
most conductive metal
silver
what’s electron drift
current flows and electrons just drift, 1mm/sec
resistor in series
r= r1 +r2+ r3
resistor in parallel series
r= 1/r1 + 1/r2 + 1/r3
power equation
power = voltage x current
power units
watts/joules per sec
what’s 1KW
1000watts/joules per sec
what’s 1 hr
60 x 60 = 3600
what’s 1KWHr
3600 x 1000
permanent magnet
exerts forces on each other as well as unmagnetized pieces of iron, can be iron/nickel/cobalt, produces own magnetic field
compass needle
unmagnetized piece of iron
how to make magnet
heat up iron bar
what are magnetic poles in
pairs
magnetic flux density
largest magnetic field in lab in 45T, unit tesla, 10,000 Gauss
ferromagnetic
permanent, retain magnetism on own, magnetic minerals
diamagnetic
magnetized in presence in magnetic field in direction opposite to field, repels magnetic field
anomaly
measure change of paleomagnetism
why does earth have magnetic field
liquid inner core
magnetic flux density of outer space
10(-10) T and 10(-8) T
use of tesla
paleomagentism
what can disrupt magnetic fields
electricity
right hand thumb rule
current is thumb, magnetic field is fingers that curl in direction
what happens when two wires are together
exert a force
