Permanent & Induced Magnetism, Magnetic Forces & Fields (AQA GCSE Physics): Flashcards
Exam code: 8463
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Define poles.
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Cards in this collection (25)
Define poles.
The poles of a magnet are its two ends; every magnet has a north pole and a south pole.
State the law of magnetism.
Two like poles repel each other, and two unlike poles attract each other.
Two like poles ______ each other, and two unlike poles attract each other.
Two like poles repel each other, and two unlike poles attract each other.
What type of force is the attraction or repulsion between two magnetic poles?
It is an example of a non-contact force.
True or False?
A north pole and a south pole will repel each other.
False.
Unlike poles (a north and a south) attract each other; only two like poles repel.
Define a permanent magnet.
A permanent magnet is made from a permanently magnetic material (for example steel) that produces its own magnetic field and does not lose its magnetism.
Define induced magnetism.
Induced magnetism is when a magnetic material is placed in a magnetic field and temporarily becomes a magnet, with one end becoming a north pole and the other a south pole.
Name three magnetic materials.
Iron, cobalt and nickel (steel is also magnetic because it is an alloy containing iron).
How can you test whether a piece of magnetic material is itself a magnet?
Bring it close to a known magnet. If it is repelled, it is a magnet; if it can only be attracted (and never repelled), it is a magnetic material but not a magnet.
What happens to an induced magnet's magnetism when it is removed from the magnetic field?
It quickly loses most or all of its magnetism.
Magnetic materials will always be ______ to a permanent magnet, regardless of which pole is held close to it.
Magnetic materials will always be attracted to a permanent magnet, regardless of which pole is held close to it.
True or False?
The end of a magnetic material closest to a magnet becomes the same pole as the magnet's nearest pole.
False.
The nearest end becomes the opposite pole to the magnet's closest pole, which is why it is attracted.
Define a magnetic field.
A magnetic field is the region around a magnet where a force acts on another magnet or on a magnetic material (such as iron, steel, cobalt or nickel).
What does the spacing of magnetic field lines show?
The spacing shows the strength of the field: lines close together show a strong field, and lines far apart show a weak field.
Where is the magnetic field around a bar magnet strongest, and why?
It is strongest at the poles, because this is where the magnetic field lines are closest together.
Magnetic field lines always go from ______ to ______.
Magnetic field lines always go from north to south.
Define a uniform magnetic field.
A uniform magnetic field has the same strength and direction at all points; it is produced between two opposite poles held close together.
How is the direction of a magnetic field at a point defined?
It is the direction of the force that would act on a north pole placed at that point.
What piece of equipment is used to investigate the shape and direction of a magnetic field, and what does it represent?
A plotting compass is used; it behaves like a small bar magnet, and its arrow represents the north pole.
True or False?
Magnetic field lines are allowed to cross where two fields overlap.
False.
Magnetic field lines must never touch or cross each other.
What evidence suggests the Earth's core is magnetic?
In the absence of any other magnet or magnetic material, a compass needle always points north, showing the Earth produces its own magnetic field.
What magnetic pole is located at the geographic North Pole, and why?
The geographic North Pole is a magnetic south pole, because magnetic field lines point into it, attracting the north pole of a compass.
What magnetic pole is located at the geographic South Pole, and why?
The geographic South Pole is a magnetic north pole, because magnetic field lines point out of it, repelling the north pole of a compass.
The Earth's magnetic field is similar to that of a ______.
The Earth's magnetic field is similar to that of a bar magnet.
True or False?
The north pole of a compass needle is attracted to the geographic North Pole because the North Pole is a magnetic north pole.
False.
The compass north pole is attracted to the geographic North Pole because it is actually a magnetic south pole.
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