Magnet Basics
What is a magnetic field?
A region around a magnet where magnetic forces can act.
What creates the magnetic field in an electromagnet?
An electric current flowing through the wire.
Name a similarity
Both produce magnetic fields.
Electromagnet is weak—improve it
Add more coils, increase current, add iron core.
Why does a coil strengthen the field?
Because each loop creates a magnetic field, and they combine to make a stronger overall field.
What are the poles of a magnet?
N & S
Why does it stop working when the battery is removed?
Because the current stops, so no magnetic field is produced.
Name a difference
Electromagnets need a current, permanent magents do not.
Why used in doorbells?
Because they can turn on/off quickly using current.
T or F: Magnetism only exists when objects touch
False, magnetism is a non-contact force.
What happens when like poles meet?
They repel
What does the coil do?
It concentrates and strengthens the magnetic field by looping the wire so fields combine
Which can be turned off and why?
Electromagnets, because they depend on electric current.
Why not permanent magnets in cranes?
They can’t be turned off, so you couldn’t release the metal.
T or F: The battery is the magnet in an electromagnet.
False - the current in the wire makes the field.
What materials are magnetic?
Materials like, Iron, Nickel, Cobalt, Steel
What role does the iron core play?
It strengthens the magnetic field by becoming magnetised and concentrating the field.
Which is used in a scrapyard crane and why?
Electromagnets, because they can be turned on/off to pick up and release metal.
Halve the coils—what happens?
Magnetic field becomes weaker because fewer loops = less combined field.
Explain an electromagnet in one sentence
An electromagnet is created when electric current flows through a coil of wire, producing a magnetic field that can be strengthened with an iron core.
Describe a magnetic field pattern
Field lines go from the North pole to the South pole and form closed loops.
How can you make it stronger?
Increase current, add more coils, or use an iron core.
Which has permanently aligned domains?
Permanent magnets
Increase current—what happens?
Magnetic field becomes stronger
Why does iron increase strength?
Iron becomes magnetised and helps concentrate the magnetic field.