Untitled Deck Flashcards
What are magnetic materials?
Materials that are attracted or repelled by magnets
Examples include iron, nickel, cobalt, steel, and magnadur.
What is a magnetic dipole?
An atom that behaves as a magnet, having a north pole and a south pole.
What happens to atomic dipoles in a magnetic material when it is unmagnetised?
The dipoles are arranged such that their magnetic fields are not experienced outside the material.
What occurs in a magnetic material when exposed to a strong magnetic field?
The dipoles align with the field, and the material becomes magnetised with a north pole (N) and a south pole (S).
What is the relationship between similar and unlike magnetic poles?
Similar magnetic poles repel and unlike magnetic poles attract.
How does the force between magnets change with distance?
The force diminishes rapidly with increased separation of the magnets.
What is magnetic induction?
The process by which magnetic properties are transferred from one body to another without physical contact.
What is the only true test for the polarity of a magnet?
Repulsion.
What defines permanent magnets?
Materials like steel that retain their magnetic properties over time.
What are examples of permanent magnetic materials?
- Magnadur
- Alnico
- Ticonal
- Alcomax
What are temporary magnets?
Materials like iron that only exhibit magnetic properties when in a magnetic field.
What are examples of temporary magnetic materials?
- Mumetal
- Stalloy
What is a magnetic field?
The region in which a body experiences a force due to its magnetic polarity.
How is the direction of a magnetic field determined?
By the direction of motion of a free north pole placed in the field.
What are the key features of magnetic field lines?
- They never cross or touch.
- There is longitudinal tension within each line.
- There is lateral repulsion between lines that are close.
- The field is uniform where lines are parallel and evenly spaced.
- The field is stronger where lines are more concentrated.
- They are directed from a north pole to a south pole.
What causes forces of attraction between dissimilar magnetic poles?
Longitudinal tension within the field lines joining them.
What causes forces of repulsion between similar magnetic poles?
Lateral push between the field lines passing close to each other.
Describe the process of mapping the magnetic field of a bar magnet using a plotting compass.
Position the compass near the N pole, mark the positions, and continue until reaching the other end, joining dots to indicate direction.
How can the magnetic field of a bar magnet be visualized using iron filings?
Sprinkle iron filings on a card over the magnet and tap gently to reveal the pattern.
What characterizes a uniform magnetic field?
Evenly spaced and parallel field lines in the central region between plane, facing magnetic poles.
What is the composition of the Earth’s core that contributes to its magnetic field?
Iron and nickel.
What does a directional compass point towards?
The north pole of the Earth, which is towards the south pole of the magnet within the core.
