electromagnetism Flashcards
What causes a magnetic field
A current flowing through a wire
What devices depend on the magnetic effect of electric currents
Electric motors
How can you show that a current is causing a magnetic field (iron)
put iron fillings on a card and pass a wire through the card, once current starts flowing, the iron fillings will start to make circular patterns because the iron fillings are lining up with the direction of the magnetic field
What can you use to find the direction of a magnetic field
Plotting compasses
what does the direction of the magnetic field depend on
The direction of the current, so if the direction of the magnetic field changes, so does the direction of the current
What does the strength of the magnetic field depend on
The size of the current, the higher the current the stronger the field
Where is the magnetic field strongest
Closer to the wire and it gets weaker as the distance increases
What is a solenoid
If a wire is made into a coil. When a current flows through it, it becomes an electromagnet
Where do solenoids have a strong and weak magnetic field and why
On the inside is strong because the magnetic fields produced by each coil of wire point in the same direction, causing them to overlap, making the magnetic field stronger on the inside.
on the outside it is weak because the magnetic field lines spread from one end of the solenoid to another, which has a bigger distance so the magnetic field becomes weaker. The magnetic field lines also cancel out in some directions
What is an electromagnet
A coil of wire with a current flowing through it
How can an electromagnet be made stronger
By putting a piece of iron in the coil. (iron core)
What is a temporary magnetic
Only magnetic when the field from the electromagnet is affecting it
