Magnetism
What is the property of attracting objects made of iron, nickel, and cobalt?
Magnetic Fields
The region around a magnet where a force acts on another magnet or magnetic material.
attract
The Rules of Magnetism state that opposite magnetic poles __________ each other, while like magnetic poles repel each other.
Magnetic Forces
These are non-contact forces–this means that magnets affect each other without touching.
Iron, steel, nickel and cobalt
Give one example of a magnetic material.
Permanent Magnets
Magnets made from materials like iron that always produce a magnetic field.
Key features of a permanent magnet
These include its ability to generate a magnetic field without the need for an external power source, and its capacity to retain its magnetism over a long period of time.
Induced Magnets
Materials that become magnets only when placed in a magnetic field and lose magnetism when removed.
Magnetic
Testing for magnetism involves using a compass to detect the presence of a magnetic field. If the compass needle aligns with the direction of the magnetic field, the object is considered to be _________.
Magnetic Field
It is the region around a magnet where a force acts on another magnet or on a magnetic material.
Magnetic Compass
A tool with a bar magnet that aligns with Earth's magnetic field or a magnet's field.
Solenoid
This consists of a wire coiled up into a spiral shape.
Motor Effect
Interaction between a wire carrying current and a magnetic field, causing a force on the wire.
Motor Effect
The ___________ is the phenomenon where a current-carrying conductor in a magnetic field experiences a force perpendicular to both the field and the current direction.
Fleming’s Left-hand Rule
Rule to determine the direction of the force on a wire in a magnetic field.
Force on a conductor (at right angles to a magnetic field) carrying a current = magnetic flux density Ă— current Ă— length
The equation for calculating electric force.
Electric Motors
A coil of wire carrying a current in a magnetic field experiences a force that tends to make it rotate.
AC Motor
A(n) __________ is an electric motor that operates on alternating current, changing direction periodically to produce rotational motion.
DC Motor
A device that converts electrical energy into mechanical energy through the interaction of a magnetic field and electric current.
Loudspeakers
In these devices, variations in an electric current cause variations in the magnetic field produced by an electromagnet. This causes a cone to move, which creates pressure variations in the air and forms sound waves.
Electromagnetic Induction
Creation of a potential difference in a conductor due to movement in a magnetic field.
Electric Potential
Potential Difference is the difference in __________ between two points in an electric circuit, representing the energy transferred per unit charge.
Magnetic Flux
Factors affecting the induced potential include the rate of change of ____, the number of turns in the coil, and the strength of the magnetic field.
Electromagnetic Induction
A potential difference can be induced (created) in a conductor when there is movement between the conductor and a magnetic field.
Alternators
Devices producing alternating current by rotating a coil in a magnetic field.
Dynamos
Devices generating direct current by rotating a coil in a magnetic field with a split ring commutator.
Half
In a dynamo, a split ring commutator changes the coil connections every ____ turn.
Microphone
A device that converts sound waves into electrical signals.
Transformers
Devices changing the potential difference of alternating current using two coils and an iron core.
Step-up transformer
A transformer where the potential difference in the secondary coil is higher than in the primary coil.
Step-down transformer
A transformer where the potential difference in the primary coil is higher than in the secondary coil.