Magnetism Flashcards
All 24 cards in this deck
What happens when two like magnetic poles are brought together?
They repel.
e.g. north and north push apart.What happens when two unlike magnetic poles are brought together?
They attract.
e.g. a north pole and a south pole pull together.Which four metals are magnetic materials at GCSE?
Iron, steel, cobalt and nickel.
True or false? All metals are attracted to a magnet.
False. Only magnetic materials such as iron, steel, cobalt and nickel are attracted; metals like copper and aluminium are not.
What is a magnetic force between two magnets an example of?
A non-contact force — it acts without the magnets touching.
True or false? Two magnets can only ever attract each other.
False. Two magnets attract if unlike poles face each other and repel if like poles face each other.
What is a permanent magnet?
A magnet made of a magnetically hard material that produces its own magnetic field all the time.
What is an induced magnet?
A magnetic material that becomes a magnet only while it is placed in a magnetic field.
Why is the force between a permanent magnet and an induced magnet always attraction?
The poles induced in the material always face the magnet as unlike poles.
Which material is used for temporary magnets, and which for permanent magnets?
Soft iron for temporary magnets; steel (or cobalt/nickel alloys) for permanent magnets.
What are the steps of an experiment to show induced (temporary) magnetism?
e.g. using a bar magnet, an iron nail and paper clips- Touch the iron nail to one pole of the bar magnet.
- Hold the free end of the nail near the paper clips — it picks them up, so it has become magnetised.
- Remove the bar magnet — the clips fall off, showing the magnetism was induced and temporary.
True or false? An induced magnet keeps most of its magnetism when the magnetic field is removed.
False. Induced magnetism in a soft material like iron is lost almost completely when the field is removed.
In which direction do magnetic field lines point?
From the north pole to the south pole of the magnet (outside the magnet).
How does the spacing of magnetic field lines show the strength of the field?
The closer together the lines, the stronger the field.
Where is the magnetic field of a bar magnet strongest?
At the poles, where the field lines are most concentrated.
What is a uniform magnetic field, and how is it drawn?
A field with the same strength and direction everywhere, drawn as parallel, equally spaced lines.
e.g. between the opposite poles of two facing magnets.True or false? The magnetic field around a single bar magnet is uniform.
False. It is non-uniform — the lines curve and are closer together near the poles.
What are the steps to use a plotting compass to trace the field around a bar magnet?
e.g. a bar magnet on a sheet of paper- Place the compass near one pole and mark dots at each end of its needle.
- Move the compass so its tail sits on the last dot, and mark the new tip.
- Repeat to the other pole, then join the dots and add an arrow from north to south.
True or false? A plotting compass needle points along the direction of the magnetic field at that point.
True. Its north end points in the field direction.
What is the behaviour of a magnetic compass evidence for?
That the Earth's core is magnetic, producing the Earth's own magnetic field.
Why does a compass needle align with the Earth's magnetic field?
The needle is a small magnet, so it rotates until its poles line up with the field.
True or false? The Earth's magnetic field is caused by the atmosphere.
False. It is produced by the Earth's magnetic core.
How can a plotting compass be used to show the Earth's magnetic field?
Place it away from any magnets or iron and note that the needle always settles pointing north–south.
Which magnetic pole must lie near the Earth's geographic North Pole?
A magnetic south pole — it attracts the north end of a compass needle.