Magnetism & Electromagnetism Flashcards
(18 cards)
What is a magnetic field?
The region around a magnet where magnetic forces act.
What direction do magnetic field lines go?
From the north pole to the south pole.
Where is the magnetic field strongest?
At the poles of the magnet.
Name three magnetic materials.
Iron, cobalt, and nickel.
What is a compass used for in physics?
To show the direction of a magnetic field.
What creates a magnetic field around a wire?
A current flowing through the wire.
What shape is the magnetic field around a current-carrying wire?
Circular around the wire.
What increases the strength of a magnetic field in a wire?
Increasing current or using a coil (solenoid).
What is a solenoid?
A coil of wire that produces a strong, uniform magnetic field when current flows through it.
How can you make an electromagnet?
Wrap a coil of wire around an iron core and pass current through it.
What are two advantages of electromagnets over permanent magnets?
They can be turned on/off and their strength can be changed.
What is the motor effect?
A force experienced by a wire carrying current in a magnetic field.
What is the motor effect used in?
Electric motors, speakers, and other devices
What rule is used to find the direction of the force in the motor effect?
Fleming’s Left-Hand Rule.
In Fleming’s Left-Hand Rule, what do the fingers represent?
Thumb = Motion (force),
First finger = Field,
Second finger = Current
What is the equation for the force on a current-carrying wire?
Force = Magnetic field × Current × Length
What is the magnetic field inside a solenoid like?
Strong and uniform (straight and evenly spaced lines).
What is the purpose of the iron core in an electromagnet?
It increases the strength of the magnetic field.
