The poles of a magnet are the places where the magnetic forces are strongest
When twomagnets are broughtclosetogether, they exert a force on each other
Two like poles repel each other
Two unlike poles attract each other
Attraction and repulsion between two magnetic poles are examples of non-contact force
A permanent magnet produces its own magnetic field
An induced magnet is a material that becomes a magnet when it is placed in a magnetic field
Induced magnetism always causes a force of attraction
When removed from the magnetic field, an induced magnet loses most/all of its magnetism quickly
A permanent magnet is a material that produces its own magnetic field regardless of circumstances. An induced magnet is a material that is magnetic only when it is placed in a magnetic field.
The region around a magnet where a force acts on another magnet or on a magnetic material (iron, steel, cobalt and nickel) is called the magnetic field
The force between a magnet and a magnetic material is always one of attraction
The strength of the magnetic field depends on the distance from the magnet. The field is strongest at the poles of the magnet
The direction of the magnetic field at any point is given by the direction of the force that would act on another north pole placed at that point
The direction of a magnetic field line is from the north (seeking) pole of a magnet to the south (seeking) pole of the magnet
A magnetic compass contains a small bar magnet
The Earth has a magnetic field
The compass needle points in the direction of the Earth’s magnetic field
explain how the behaviour of a magnetic compass is related to evidence that the core of the Earth must be
The behaviour of a compass shows that the Earth has a magnetic field which means that the core of the Earth must be magnetic. Scientists believe that this field is produced by convection currents. in the Earth's core, which is made from iron and nickel.
When a current flows through a conducting wire a magnetic field is produced around the wire. The strength of the magnetic field
depends on the current through the wire and the distance from the
wire.
Shaping a wire to form a solenoid increases the strength of the
magnetic field created by a current through the wire. The magnetic
field inside a solenoid is strong and uniform.
The magnetic field around a solenoid has a similar shape to that of
a bar magnet. Adding an iron core increases the strength of the
magnetic field of a solenoid.An electromagnet is a solenoid with an
describe how the magnetic effect of a current can be demonstrated
Plotting compasses on a piece of paper with a wire running through it will demonstrate this rule
explain how a solenoid arrangement can increase the magnetic effect of the current.
The small magnetic fields caused by the current in each turn of the coil add together to make a stronger overall magnetic field.
When a conductor carrying a current is placed in a magnetic field the magnet producing the field and the conductor exert a force on
each other. This is called the motor effect.
factors that affect the size of the force on the conductor
Current,magnetic flux density and length
A coil of wire carrying a current in a magnetic field tends to rotate. This is the basis of an electric motor
F=BIL
force, F, in newtons, N magnetic flux density, B, in tesla, T
current, I, in amperes, A (amp is acceptable for ampere)
length, l, in metres, m
When a current is passed through the coil, the coil spins because the force on the left hand side acts upwards & the force on the right hand side acts downward.
Factors that affect the size of a conductor are
Current: The larger the current, the larger the force. Length: The longer the length of the conductor, the larger the force.
Magnetic Flux Density: The higher the density, the more magnetic field lines and the larger the force on the conductor.
All magnets have two poles: north (or north seeking) and south (or south seeking)
All magnets produce a magnetic field, a region where other magnets or magnetic materials (e.g. iron, steel, nickel, and cobalt) experience a non-contact force
Magnetic field lines always go from north to south and show the direction and strength of the magnetic field
The closer together the magnetic field lines are, the stronger the magnetic field and the stronger the force acting on a north pole placed in that point in the field
The magnetic field is strongest at the poles of a magnet, where the magnetic forces are also strongest
The force between a magnet and a magnetic material is always attractive, regardless of the pole
Inside a compass is a tiny bar magnet, and the north pole of this magnet is attracted to the south pole of any other magnet it is near, pointing the compass in the direction of the magnetic field
You can move a compass around a magnet and trace its position on paper to visualize the magnetic field
There are two types of magnets: permanent magnets and induced magnets
If two poles of a magnet are put near each other, they will exert a force on each other, which can be attractive or repulsive
Compasses always point north when not near a magnet because the Earth generates its own magnetic field
Permanent magnets produce their own magnetic field, while induced magnets are magnetic materials that turn into a magnet when put into a magnetic field