Physics Flashcards
what is a magnet
a magnet is an object or material that creates a magnetic field
How do you draw magnetic field lines
1)draw a bar magnet with north and south pole.
2)draw lines going in from one pole and out through the other(include arrow for direction)
3) draw lines going from the top of one pole to another. do the same for the bottom
What does the lines being closely together mean
the more dense the field lines, the stronger the magnetic field is in that area
how do we find the field lines
use a compass
1)the needle of the compass has tiny bar magnet which lines up with field line of whichever magnetic field put in.
2)it will then point towards south pole and tell you where north pole is
how to show the interaction between two like poles(the same)
The interaction will repel
1)draw two bar magnets that are the same . and draw lines going for both poles going outwards in opposite direction
how to show the interaction between two unlike poles
the interaction will attract
1)draw two bar magnets that are different. and draw lines going from one pole into the other.
what is a magnetic material
any object that has potential to become a magnet
4 Types of magnetic materials
iron, cobalt,steel,nickel
what is a permanent magnet
produces own magnetic field
what is an induced magnet
has magnetic field temporarily
what is the force between an induced and permanent magnet
always attractive
What is a material called when it loses magnetism easily
magnetically soft
name a material that loses magnetism quickly
iron
what is a material called when it loses magnetism slowly
magnetically hard
name a material that loses magnetism slowly
steel
what does electromagnetism mean
where electric current produces own magnetic field
what is the right hand rule
when your thumb shows the direction of the current and the rest of your coiled hand shows direction of magnetic field
how do you use the right hand rule
curl you hand and put your thumb up
2)your thumb will the point in the currents direction
3)your fingers will point towards magnetic field direction
what is a solenoid
cylindrical coil of wire
what is the magnetic field like inside the solenoid
strong and uniform
what happens if you bend the current carrying wire inside the solenoid
increases the strength of the magnetic field produced
By reversing the direction of the magnetic field you….
reverse the direction of the current
4 ways to increase an electromagnets strength
increase current
increase number of coils while keeping length the same
decrease the length
add iron core through the middle
what is the motor effect
a current carrying wire in a magnetic field experiencing a force
how does the motor effect work
a current carrying wire will produce own magnetic field
if you place a wire between north and south pole (as they carry produce magnetic field )
the two magnetic field will interact which puts force on the wire
how can a wire experience full force in the motor effect
by putting it perpendicular(90 degrees)
what is flemings left hand rule
thumb=direction of the force
finger=direction of magnetic field
middle finger= direction of the current
how to calculate the strength of the force
F=BIL
force= magnetic flux density x current x length
what is an electric motor
a current carrying wire in a magnetic field rotating
what is a split ring commutator
keeps the motor spinning in one direction
how does the split ring commutator make the coil rotate in 1 direction
current flows through the coil, creating a magnetic field around it.
This interacts with the magnetic field of the permanent magnets, producing a force on each side of the coil
The forces act in opposite directions on each side, making the coil rotate.
After half a turn, the coil would stop or reverse because the forces would push in the opposite direction.
The split-ring commutator reverses the current every half-turn, which reverses the direction of the forces.
three ways to increase speed in electric motor
increase current
add more turns to the coil
increase magnetic flux density
