CP12/13 -Magnetism And Electromagnetic Induction Flashcards
What is a permanent magnet?
A magnetic material that constantly produces its own magnetic field.
What is an induced magnet?
A material that becomes magnetic when placed in a magnetic field
It is temporary
What sides attract and repel?
Opposites attract
Same sides repel
How can you use a plotting compass to draw a magnetic field?
Place the compass near the magnet on a piece of paper
Mark the direction the compass needle points
Move the compass around repeatedly marking
Join the points to show the field lines
At which pole does the magnetic field always flow?
Into South
Out North
What is a magnetic field?
The area surrounding a magnet that can exert force on other magnetic materials.
How does a compass work?
The needle is a small magnet
The Earth creates a giant magnetic field
The magnet is attracted to the North Pole of the Earth
Name some magnetic materials that are attracted by magnets:
Nickel
Iron
Steel
Cobalt
What are some key features of magnetic fields?
The field lines never cross each other
The closer the lines the stronger the magnetic field
The arrows show the direction of the force exerted
Explain the magnetic field produced when a current flows in a wire?
A circular magnetic field around the wire
Magnetic field strength is stronger closer to the wire
What can you use the Right Hand Rule to find?
Direction of the current
Direction of the magnetic field
What is a solenoid?
A coil of wire which can carry an electric current to create a magnetic field
Describe the magnetic field lines of a solenoid?
The field lines inside the solenoid are uniform and strong
The further away you get from the solenoid the weaker the magnetic field
What is an electromagnet?
A coil of wire with a current flowing through it
How can you increase the strength of an electromagnet?
By placing an iron core inside the coil, which becomes a temporary magnet
What is the motor effect?
The effect where a force is exerted on a wire carrying a current in a magnetic field
Explain the motor effect:
The current in a wire creates a magnetic field around the wire
This magnetic field interacts with the magnetic field between two magnets
The force is greatest when the wire is at right angles to the magnets
Explain Flemings Left Hand Rule:
Your thumb is the direction force is exerted
Your index finger is the direction of the magnetic field
Your middle finger is the direction of the current
What is electromagnetic induction?
The production of a potential difference when a conductor is moved through a magnetic field
If the conductor is part of an electric circuit an induced current will flow
What is the generator effect?
When motion between a conductor and magnetic field creates electricity
What are two ways electromagnetic induction can occur?
A coil of wire is moved into a magnetic field
A magnet is moved into a coil of wire
How do you increase the potential difference in electromagnetic induction?
Increase the speed of the movement
Increase the magnetic field strength
Increase number of turns in the coil
How do you increase magnetic field strength?
Increase number of turns in a coil
Increase the current
Add an iron core to a solenoid
What is a transformer?
An electrical device that increases or decreases the potential difference of an alternating current
