P7 Magnetism and Electromagnetism Flashcards
What happens when two magnets are brought close together?
Like poles repel each other.
Unlike poles attract each other.
What materials are magnetic?
Iron, steel, cobalt, and nickel are magnetic materials.
What is the difference between a permanent magnet and an induced magnet?
Permanent magnet: Produces its own magnetic field and is able to attract and repel other magnetic materials
Induced magnet: Becomes a magnet only when placed in a magnetic field and loses most/all magnetism when removed. It is only able to attract other magnetic materials
What is a magnetic field?
The region around a magnet where a force acts on another magnet or a magnetic material.
How does distance affect magnetic field strength?
The strength of the magnetic field decreases as the distance from the magnet increases.
The field is strongest at the poles.
What is the direction of a magnetic field
The direction is given by the force on a north pole placed at that point.
Magnetic field lines go from north to south.
What is a magnetic compass and what does it show?
A magnetic compass contains a small bar magnet.
The needle points in the direction of the Earth’s magnetic field.
How does a magnetic compass provide evidence that the Earth’s core is magnetic?
The needle of a compass aligns with the Earth’s magnetic field, indicating that the Earth’s core is magnetic.
How can we plot the magnetic field of a magnet using a compass?
Place the magnet on a sheet of paper.
Place a compass near the magnet and mark the direction the needle points.
Move the compass to the next point and continue marking the directions.
Join the marks to show the field lines.
What is the magnetic effect of a current?
When a current flows through a wire, a magnetic field is produced around it.
What affects the strength of the magnetic field around a wire?
Current: Increasing the current increases field strength.
Distance: The field is stronger closer to the wire.
How can the magnetic field of a current-carrying wire be demonstrated?
Place a compass near the wire; when current flows, the compass needle deflects, showing a magnetic field is present.
What is the shape of the magnetic field around a straight wire?
Concentric circles around the wire, with the direction determined by the right-hand grip rule.
What is a solenoid?
A coil of wire that generates a strong magnetic field when a current flows through it.
How does a solenoid increase the magnetic effect?
The magnetic fields of each coil combine, creating a stronger and more uniform field.
What is the shape of the magnetic field around a solenoid?
Similar to that of a bar magnet, with a north and south pole.
What is an electromagnet?
A solenoid with an iron core that greatly enhances the magnetic field strength.
How can you increase the strength of an electromagnet?
Increase the current.
Add more turns to the solenoid.
Use a soft iron core.
What is Fleming’s Left-Hand Rule?
Thumb: Direction of the force (motion).
First Finger: Direction of the magnetic field (north to south).
Second Finger: Direction of the current (+ to -).
What factors affect the size of the force on a conductor?
Magnetic field strength (stronger field = greater force).
Current (higher current = greater force).
Length of wire in the field (longer wire = greater force).
